Species criteria biology 11. Species criteria

Abstract of a lesson in biology grade 11.

"View. View criteria. "

The purpose of the lesson:   to form knowledge about the species, its criteria and structure; to reveal the essence of genetic processes in populations and their results; prove the evolutionary role of mutations.

Tasks:

1. Educational:

• give a definition of the concept of “view”;
• be able to name the criteria for the species and justify the importance of the criteria for determining the species;
• to prove that the species objectively exists in nature;

2 developing:

• use elements of causal analysis to explain observations of biological objects;
• develop skills in an interactive way of gaining knowledge;

3. Educational:

• to develop the ability to speak in front of an audience and express their opinion;
• to bring up an emotionally holistic attitude to modern problems of heredity.
• to form the students' interest and positive attitude towards the study of the history of biology.

Equipment: Table “Mutational variability of plants and animals”, indoor plants, pictures of mutant forms, handouts according to species criteria, collection of insects (different species of ground beetles), herbarium of plants (white clover and red clover), postcards with a picture of a polar bear and a brown bear, computer presentation.

During the classes:

1. Organizing time

• note missing
• i set the class to work
• checking readiness for the lesson.

Frontal survey.

What are the main driving forces of evolution.

What is artificial selection?

What is the struggle for existence? What are its forms?

What form of struggle is the most intense and why?

What is natural selection?

2. Introductory conversation.

One of the main features of biological matter on our planet is its diversity. This is expressed in the fact that it is represented by individual species. The species diversity of living organisms on our planet is very large. Now it lives about 50 thousand. plant species, more than 1.5 million animal species, at least 100 thousand. species of fungi, a large number of species of bacteria and viruses. Scientists are constantly discovering and describing new species of living organisms.

What is a view? What do we mean by this concept?

3. Communication of the purpose and topic of the lesson.

Today in the lesson we will give a definition of the species and get acquainted with the criteria and structure of the species.

4. The study of new material.

The concept of species. The basic, elementary and really existing unit of the organic world, or otherwise - the universal form of existence of life, isview (from lat. species - view, image). View - a collection of individuals with a hereditary similarity of morphological, physiological and biochemical characteristics can freely interbreed and produce prolific offspring, adapted to certain living conditions and occupy a certain area- area.

Individuals belonging to one species do not interbreed with individuals of another species, are characterized by a genetic community, a unity of origin. The species exists in time: it arises, spreads (during its heyday), can remain indefinitely for a long time in a stable, almost unchanged state (relict species) or continuously change. Some species disappear over time, leaving no new branches. Others give rise to new species.

View - main taxonomic category of biological classification.The first idea of \u200b\u200bthe species was created by Aristotle, who defined the species as a collection of similar individuals. The term “species” itself, translated from Latin, means “image”.The concept of "view" it was first introduced at the end of the 17th century. English botanist John Ray (1627-1709), who noted that different species differ in external and internal structure and do not interbreed.

A great contribution to the further development of the concept of “species” was made by the Swedish scientist Karl Linney (1707-1778). According to his ideas, species are objectively existing in the nature of education, and there are differences between different species to a greater or lesser extent. So, for example, the bear and the wolf clearly differ from each other in external signs, while the wolf, jackal, hyena, fox are more similar in appearance, since they belong to the same family - wolves. The appearance of species of the same genus is even more similar. That is why the species began to be considered as the main classification unit. This was of great importance for the development of taxonomy. Thus, the name of Linnaeus is associated with the beginning of the description and classification of living organisms. This work is ongoing.

A biological species is not only the main taxonomic unit in biological taxonomy. This is an integral structure of wildlife, which is reproductively isolated from other similar structures and has its own destiny.They give integrity to this system,  First of all, processes of interaction between individuals. The relationship between organisms of different generations, between parents and children, males and females,  features of territorial behavior - all this determines the internal structure of the form! Species characteristics do not always ensure the survival of an individual, but they are always favorable for the species as a whole. For example, a bee that has lost its sting will die, but at the same time protect the remaining individuals, the spider female eats the male after mating, it is good for the individual to be good, as most of the females die, protecting their offspring.

The second reason for maintaining the unity and integrity of the species isreproductive isolation, i.e. the impossibility of crossing with individuals of a different species. This is how protection is carried out.gene pool of the species ( the entire set of genes of the species) from the influx of foreign genetic information. There are various factors that prevent interspecific crossbreeding. For example, in California, two closely related species of pine grow. In one of them, pollen spills out in early February, and in the other in April, therefore, between these speciesseasonal isolation. In higher animals, mating behavior has characteristic species features, so females of one species do not respond to courtship of males of another close species - this is an examplebehavioral isolation.

The presence of reproductive isolation in natural conditions is a decisive factor in determining a species as a genetically closed biological system.

The question of defining organisms for one or different species is very complex and arouses controversy among scientists in the scientific community. For the species determination procedure, species criteria are used.View criteria are characteristics by which one species differs from another.  The issue of species criteria is central to evolutionary theory. This is understandable: a clear understanding of the nature of the species is necessary to identify the mechanisms of the evolutionary process

The situation for the decision of students in the class.

Three plants of the genus geranium are proposed: white geranium, red geranium, pink geranium. Do these plants belong to one or different species? Argument your answer. Based on the results of solving the problem situation, a definition is given.morphological criterionkind of.

This was the first and for a long time the only criterion for describing the species. Based on this criterion, C. Linney constructed his Nature System. The morphological criterion is the most noticeable and convenient, and it is now widely used in the taxonomy of plants and animals. We can easily distinguish the size and color of the plumage of a large spotted woodpecker from green, a great tit from a crested and long-tailed, clover meadow and lupine.
Despite the convenience, this criterion does not always “work”. You will not use it to distinguish between twin species that are practically no morphologically different. There are many such species among malaria mosquitoes (6 twin species), Drosophila, whitefish. Even in birds, 5% of species are doubles, and in one row of North American crickets there are 17 of them, a black rat (2 species with 38 and 49 chromosomes). Using one morphological criterion can lead to erroneous conclusions. So, K. Linney, according to the structural features, assigned the male and female mallards to different species. Now that it has been established that a species can have many forms, the morphological criterion does not always satisfy scientists. Nevertheless, it should be recognized that this criterion is very convenient for systematizing species and for most animal and plant determinants it plays a major role.

Genetic (cytomorphological) criterion. Sometimes, among very similar individuals, groups are found that do not interbreed. The vast majority of species are characterized by a strictly defined karyotype — a specific set of chromosomes (quantity, shape, size, structure, DNA composition). Individuals of different species have different sets of chromosomes. A different number of chromosomes in the karyotype of different species provides genetic isolation during interspecific crossing, because it causes the death of gametes, zygotes, embryos or leads to the birth of infertile offspring (hinnies - a hybrid of a horse and a donkey). It is the use of the genetic criterion that makes it possible to reliably distinguish twin species. However, this criterion is not universal. First, in many species the number of chromosomes is the same and their shape is similar. For example, some species of the legume family have 22 chromosomes (2n \u003d 22). Secondly, individuals with a different number of chromosomes can occur within the same species, which is the result of genomic mutations (poly- or aneuploidy). For example, goat willow may have a diploid (38) or tetraploid (76) number of chromosomes.

Physiological criterion.The physiological characteristics of various species of plants and animals are often a factor ensuring their genetic independence.Physiological criterionreflects the similarity of all vital processes in individuals of one species: the same methods of nutrition, reproduction, similar reactions to external stimuli, the same biological rhythms (periods of hibernation or migration). For example, in two close species of the fruit fly of Drosophila, sexual activity is observed at different times of the day: in one species in the morning, and in the other in the evening. For example, in many Drosophila, the sperm of an alien species elicits an immunological reaction in the female genital tract, and a hundred results in the death of sperm. Hybridization of various species and subspecies of goats often leads to a violation of the periodicity of fruiting - the offspring appears in winter, which leads to its death. Crossing of different subspecies of roe deer, for example, European and Siberian, sometimes leads to the death of a female due to a large offspring.

However, there are exceptions. For example, dogs can produce offspring when mating with a wolf. Fruits can be hybrids of some species of birds (canaries, finches), as well as plants (poplar, willow). T.O. this criterion is also insufficient to determine the species affiliation of individuals.

Biochemical criterionallows species to be distinguished by the composition and structure of certain proteins, nucleic acids, etc. Individuals of one species have a similar DNA structure, which leads to the synthesis of identical proteins that differ from proteins of another species. However, in some bacteria, fungi, and higher plants, the DNA composition turned out to be very close. Therefore, there are double species also by biochemical characteristics.

Environmental criteriabased on the fact that each species can exist only in certain conditions, performing its characteristic functions in a specific biogeocenosis. It is characterized

certain forms of relationships of organisms of a given species with representatives of other species and factors of inanimate nature, i.e., the conditions in which this species is found in nature. In Texas, closely related oak species grow on different soils: one species

it is found only on limestone soil, another on sandy soil, and the third grows on the outcrops of igneous rocks. So, for example, caustic buttercup grows in floodplain meadows, creeping buttercup - along the banks of rivers and ditches, burning buttercup - in wetlands. However, there are species that do not have strict ecological confinement. These include many weeds, as well as species under the care of humans: indoor and cultivated plants, domestic animals.

Geographic criteriabased on the fact that each species occupies a certain territory or water area, called the range. It can be larger or smaller, intermittent or continuous. However, a huge number of species has overlapping or overlapping ranges. In addition, there are species that do not have clear boundaries of distribution, as well as cosmopolitan species that live on vast expanses of land on all continents or the ocean (for example, plants — shepherd’s bag, medicinal dandelion, species of nestling, duckweed, reed, synanthropes — bed bug, red cockroach, housefly). Therefore, the geographical criterion, like others, is not absolute. Due to these circumstances, the geographical criterion cannot be universal.

Ethological criterion.For some species of animals, the mechanism that interferes with crossing is their behavior, especially during the mating season. Recognition of partners of their own species and the rejection of attempts to courtship males of another species are based on specific stimuli - visual, sound, chemical, tactile, mechanical, etc. In the widespread genus, the scallops different species are very similar morphologically, in nature they cannot be distinguished by color nor in size. But they all differ well in song and habits. The song of the warbler’s warbler is complex, similar to the song of the early bird, but without the final ring, and the song of the shadow is simple monotonous whistle. Numerous twin species of American fireflies were first identified only by differences in their light signals. Firefly males produce flashes of light in flight, the frequency, duration and alternation of which is specific to each species. Differences in demonstrative behavior often play a decisive role in reproductive isolation. For example, close species of Drosophila flies differ in the specificity of the courtship ritual (by the nature of the vibration of the wings, trembling of the legs, whirling, tactile contacts).

Historical criterion. Common ancestors, a single history of the appearance and development of the species.

Thus, to determine the species affiliation of an organism, it is necessary to use all the criteria in the aggregate, because individual criteria for different species may coincide.

Species represent a certain level of organization of living matter-species.

Actually in nature, individuals of any species within the range are unevenly distributed: somewhere

they form clusters, but in some places they may be absent altogether. Such partially or completely isolated groups of individuals of the same species are called  populations   (from lat. populus - people, population), i.e., in vivo any kind

consists of populations.

5. Securing new material.

The main form of life and the unit of classification of living organisms is the species. A set of criteria is used to isolate a species: morphological, physiological, geographical, environmental, genetic, biochemical. The species is the result of a long evolution of the organic world. Being a genetically closed system, it, nevertheless, historically develops and changes.

Task number 1 . The bison and bison are two species belonging to the same genus. They are very similar to each other externally and in captivity give rise to prolific offspring of bison. They do not interbreed in nature, as they live on different continents - the bison in Europe, and the bison in North America. What can be called this view criterion?

Task number 2 . It has been established that under the name "black rat" two species are hidden - a double: rats with 38 and 42 chromosomes. They do not interbreed with each other. What can be called such a criterion?

Task number 3 Between closely related species there is a clear separation of ecological niches. For example, some species of robins in coniferous forests, at first glance, occupy one niche, but some of them feed on the external, and others on the internal branches of the trees. What is the fundamental criterion in this case?

Task number 4. Determine the systematic position of the depicted plants. Describe each plant by morphological criteria.

Task number 5. Chimpanzee hemoglobin in amino acid sequence does not differ from human hemoglobin, and in gorilla - two differences in the amino acid sequence. What criteria are we talking about?

Task number 6. At the very beginning of the nineteenth century in biology, a dilemma developed in views on the problem of species, which can be expressed with one phrase: “Either species without evolution, or evolution without species.” Explain the meaning of this expression, with the works of which scientists are associated such views on the problem of the species?

Task number 7. In two lakes that are not communicated with each other, various species of fish live: crucian carp, roach, ide, bream, pike perch.

A) how many fish populations live in the second lake?

B) how many fish populations live in the first lake?

C) how many species of fish live in two lakes?

D) how many fish populations live in two lakes?

1. What is a view? What are the types of plants, animals, and mushrooms known to you that are found in your area.
2. What criterion, in your opinion, is the most obvious and understandable? What other criteria exist? Describe them.

1. Two cultivated plants - barley and rye have the same number of chromosomes (14), but do not cross; have differences in the external structure; their seeds differ in chemical composition (usually bread is not baked from barley flour). Based on what criteria will you prove that these plants belong to different species?
2. On the basis of what knowledge can environmental and geographical criteria be established?

6. Performance assessment and homework.

1. Assess the degree of implementation of the goals.
2. Assess the work of students during the lesson.

D / Assignment p. 40-45 c.1-6 p. 43.43 Find data that refutes Darwin's theory.

A large variety of living organisms live on planet Earth. Fish, birds, insects and others. They are all different and different from each other. But there is a strict order in this variety. All life on earth exists in the form of species.

Before you is the systematic position of the brown bear. He belongs to the kingdom of animals. Type Chordovye. Subtype Vertebrates. Class Mammals. Predatory squad. The Bear family. Family Bears. Kind Brown bear. View  is the smallest systematic category.

Individuals belonging to one species generally do not interbreed with individuals of another species, are characterized by a genetic community and a unity of origin.

View - this is a historically established set of populations whose individuals have a hereditary similarity of morphological, physiological and biochemical characteristics, can freely interbreed and produce prolific offspring, adapted to certain living conditions and occupy a certain area - area .

Biological view - This is not only a systematic category. This is an element of wildlife, - isolated from other species.

The concept of “view” was first introduced at the end of the 17th century. English botanist John Ray, who noted that different species differ in their external and internal structure and do not interbreed.

A great contribution to the further development of the concept of “species” was made by the Swedish scientist Karl Linney.

Karl Linney

According to his ideas, species are formations objectively existing in nature, and there are differences between different species to a greater or lesser extent.

So, for example, the bear and the wolf clearly differ from each other in appearance, while the wolf and the fox are more similar in appearance, since they belong to the same family - Wolfs.

Karl Linney proposed a binary nomenclature for describing species of living things, and laid the foundations for the modern classification of the living world more than 250 years ago. During this time, a huge number of species of animals and plants were discovered and classified. And the more biologists made discoveries, the more often they thought about how much is alive on Earth.

For example, a group of scientists from Canada estimated that the total number of species of living things is approximately equal to 8.7 million plus or minus 1.3 million.

According to their calculations, 2.2 million species live in the World Ocean, 6.5 million live on land. There are about 7.8 million species of animals on the planet, 611 thousand mushrooms, 300 thousand plants.

The number of species is constantly increasing, scientists annually find previously unknown to science. New species occupy free ecological niches.

In order to accurately determine whether an organism belongs to a particular species, certain criteria are used.

View criteria  - these are signs by which one species can be distinguished from another. They allow you to understand close related groups of plants and animals.

Today in the lesson we will consider: morphologist and physical criterion, physiological, geographical criterion, ecological, biochemical and genetic.

Morphological criterion

This criterion is based on the similarity of the external and internal structure between individuals of the same species. . This criterion is the most convenient and therefore widely used in taxonomy.

Morphological determination of the species

For example, a thorn swan at m, black swan, black-necked swan. We see their external differences. When crossed, they will not produce prolific offspring, because they belong to different species.

However, according to the morphological criterion, it is not always possible to accurately determine the involvement of any organism in a particular species, because in nature there are many exceptions.

Difficulties in determining species are that individuals of the same species, for example, males and females, may differ in appearance. For example, often males and females of insects, birds, and not only externally differ. This phenomenon is called sexual dimorphism.

Unpairing Mother of Pearl

Scientists often have difficulty determining the species, as some of the individuals may have seasonal  morphological variability. For example, butterflies s variable flax has a different color of wings with a temperature difference.

The spring form has a much lighter, yellow-orange color of the wings with dark spots on them. The summer form differs from the spring: - they are not red, but black, with white or yellow stripes on the wings and small orange spots. In places, the third generation of pestrocra can be found s flax. They are distinguished by a combination of orange and black.

Sometimes individuals of different species are so similar in appearance that they seem to belong to the same species. For example, how species doubles  - they are very similar in appearance, but relate to completely different species.

Double species   do not have external differences in most morphological characters, but are reproductively isolated. And only a detailed study of their external and internal structure allows us to attribute individuals to different species.

For example, a cereal pest widespread in Europe and in the temperate latitudes of Asia leaf beetle  (pi i red-breasted)), until recently, was considered a single species. And only a detailed study of the organs of several beetles allowed scientists to conclude that there is another species.

Why are there so similar species?  Perhaps in the process of speciation, genotype rearrangement is not always accompanied by changes in the phenotype morphology, which complicates the distinction between the two species. All the features of the lifestyle of any organism are somehow reflected in its appearance, size, color. For example, bright frog belly yellow-bellied vents i nki scares off enemies and at the same time serves as its characteristic sign. It lives in most of southern and central Europe.

A red-bellied toad is found in Central and Eastern Europe to the Urals. In these frogs, the difference in color is due to differences in habitats.

Physiological criterion

It lies in the similarity of life processes, primarily the possibility of crossing between individuals of the same species with the formation of prolific offspring .

Different species at different times reach puberty. Are different seasonal and daily rhythms of lifeand in nature, as a rule, do not interbreed.

Even similar wild horses like tarp but mr. Przhevalsky’s horse is not given fertile offspring when they are crossed, because they belong to different species.

However, again there are exceptions. Common fox  It populates, although with different densities, all landscape-geographical zones, starting from the tundra and subarctic forests, including mountains in all climatic zones. BUT steppe fox  lives in the steppe and forest-steppe. Despite the external differences, a cross is possible between him.

The physiological criterion is also insufficient to determine the species affiliation of individuals.

Geographic criteria

It is based on the fact that each species occupies a certain territory or water area, called the range . It can be larger or smaller, intermittent or continuous.

For example, Eurasian beaver is common in Europe and Asia. And the Canadian beaver is in North America. Externally, representatives of two different species are very similar to each other, but the Eurasian beaver is larger.

The ranges of many species overlap and overlap. In the case of coincidence of habitats, the reason for isolation is the difference in lifestyle.

For example, fruit flies and l live on the same territory in western North America. However, the cross between them does not occur, because they breed at different times of the day.

Also there are cosmopolitan species andyou that inhabit the vast expanses of land of all continents or the ocean. Therefore, the geographical criterion, like others, is not absolute.

Environmental criteria

It is based on the fact that each species can exist only in certain conditions, performing its characteristic functions in a certain biogeocenosis .

For example, caustic buttercup  grows in floodplain meadows, banewort  - in wetlands, creeping buttercup  - along the banks of the rivers.

One more example. Grass frog.  She spends most of her life on land. It spawns in water, where its offspring develops.

But pond frog.She lives mainly in water. Not only mating takes place here, but her whole life.

The life cycles of frogs are composed of several stages, their time in different species may not coincide.

For example, ponds but i am a frog laying eggs when the water has already warmed up. And herbal does this earlier, without waiting for heat. Therefore, her tadpoles come out earlier.

Each species is adapted to certain conditions of existence. Swallow shore  lives in holes on the sandy slopes of rivers.

In the countryside, another swallow nests, its specific name is rustic. In urban conditions, the third species of swallows lives - urban.  Thus, the conditions for the existence of a species are determined by an environmental criterion.

Also, to determine the species, the composition and structure of certain proteins, nucleic acids, the composition of the blood, and everything related to biochemistry are studied. This type of species definition is called   biochemical criterion.  It allows you to distinguish between species in the composition and structure of certain proteins, nucleic acids, etc.

Individuals of one species have a similar DNA structure, which leads to the synthesis of identical proteins that differ from proteins of another species. However, in some bacteria, fungi, and higher plants, the DNA composition can be very close. Therefore, there are double species also by biochemical characteristics.

Genetic criterion

It is based on the difference in species according to karyotypes. , i.e. the number, shape and size of chromosomes. The vast majority of species are characterized by a strictly defined karyotype.

For example, the above-mentioned species of Eurasian beaver and Canadian beaver are separated from each other not only by thousands of kilometers of the ocean surface, but also by a different chromosome set. Eurasians have 48, and Canadians 40.

The genetic criterion is also not universal. First, in many species the number of chromosomes is the same and their shape is similar. Secondly, individuals with a different number of chromosomes can occur within the same species, which is the result of genomic mutations (poly- or aneu-ploid and i). For example, goat willow  may have a diploid number of chromosomes (38) or tetra-ploid (76). Thus, the criteria of the species are interconnected and determine the qualitative feature of the species, but none of them is absolute.

For example, two different species may not differ in external structure and even have the same chromosome sets. But if they differ in behavior, then they do not interbreed with each other and, therefore, are isolated from one another. Only in the aggregate the listed criteria allow us to establish with sufficient reliability the belonging of an organism to one or another species.

The combination of properties and common features inherent in one species is called a view criterion. Typically, six to ten species determination criteria are used.

Systematization

Species - a systematic or taxonomic unit having a common characteristic and uniting on its basis a group of living organisms. To distinguish a biological group in one species, a number of features should be taken into account that are associated not only with distinctive external features, but also with living conditions, behavior, distribution, etc.

The concept of “species” was used to group externally similar animals into groups. By the end of the 17th century, much information had accumulated on species diversity, and the classification system required revision.

Karl Linney in the 18th century combined species into genera, and genera into squads and classes. He proposed a binary nomenclature of notation, which helped to significantly reduce the names of species. According to Linnaeus, the names began to be composed of two words - the names of the genus and species.

Fig. 1. Karl Linney.

Linnaeus was able to systematize species diversity, but he himself mistakenly distributed animals by species, relying mainly on external data. For example, attributed male and female ducks to different species. However, Linnaeus made a huge contribution to the study of species diversity:

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• classified plants by gender (dioecious, monoecious, multicompared);
• identified six classes in the animal kingdom;
• attributed a person to the class of primates;
• described about 6,000 animals;
• first conducted experiments on plant hybridization.

Later, the biological concept of the species appeared, confirming that the classification by species is natural, genetically determined, and not artificial, created by people for the convenience of systematization. In fact, a species is an indivisible unit of the biosphere.

Despite the possibilities of modern science, many species are still not described. According to 2011 data, about 1.7 million species have been described. At the same time, there are 8.7 million species of plants and animals in the world.

Criteria

By the criteria you can determine whether individuals belong to one or to different species. First of all, the morphological criterion of the species is distinguished, i.e. representatives of different species should differ in external and internal structure.

However, often this criterion is not enough to separate a group of living organisms into a separate species. Individuals may differ in behavior, lifestyle, genetics, so it is important to take into account the totality of criteria and not draw conclusions based on one attribute.

Fig. 2. Morphological similarity of species of barbel.

The table “Species Criteria” describes the most important criteria by the totality of which a species can be recognized.

None of the criteria is absolute and has exceptions to the rules:

• outwardly dissimilar species have the same set of chromosomes (cabbage and radish - 18 each), while mutations can occur within the species and populations with an excellent set of chromosomes can occur;
• black rats (twin species) are morphologically identical, but genetically not, and therefore cannot produce offspring;
• in some cases, individuals of different species cross (lions and tigers);
• areas often intersect or are torn apart (West European and East Siberian magpie range).

The concept of species, the classification of organisms as a red thread, passes through all biology courses. At the level of grade 6, we introduce children to the classification of plants, give a definition of the species. At the beginning of the 7th grade, studying the classification of animals, we again return to this concept. Further, at the level of grade 8, it is logical to give a systematic position of a person in the living world and unobtrusively recall plants and animals. It is better to remember more often, since the material is gradually realized by students and quickly forgotten. At the level of grade 9 and 11, a lesson is held on the topic "View, its criteria and structure." I believe that at the 9th grade level, the main emphasis should be on what is understood by certain criteria of the species; at level 11 - the variability of the definitions of the species, the ability to determine what criteria are involved in the description, to get acquainted with the structure of the species in nature.

Summary of the lesson.

Theme:  View, its criteria and structure.

purpose: continue to form the concept of “view”, “view criteria” among students; to consolidate the skills of students to work with texts, make tables, analyze, formulate conclusions.

Tasks:  continue to create situations in which students must independently draw conclusions; compile a table according to the criteria of the view with the help of students, consider the structure of the view, consolidate the material studied when working with prepared texts.

Equipment:  textbook A.V. Teremov, R.A. Petrosova "Biology. Biological systems and processes. Grade 11 (profile level) ”M: Mnemosyne, 2010; video film, multimedia fragments, various types of indoor plants, tables on the diversity of animals, collections.

Type of lesson: combined.

During the classes.

Organizational moment - 1 min.

Updating related knowledge“The fitness of organisms” is carried out in the form of a brief work, where specific organisms are indicated, opposite to them you need to write the type of fitness - 7 minutes

1 option

Wasp - (warning)

Stickman - (disguise)

Japanese macaque - (ethological fitness)

Giraffe- (dissecting coloring)

Green Grasshopper (patronizing)

Option 2

White hare - (patronizing)

Turtle - (passive protection)

Deaf nettle - (mimicry)

Ladybug - (warning coloring)

Migrations of birds - (ethological fitness)

Learning New Material - 25 min.

Man in nature is surrounded by a large number of species of animals and plants. Let’s remember now what we mean by a species? 3-4 students answer, then we turn to the definition of the species on page 62: “A species is a collection of individuals with morphological, physiological, biochemical, ecological and genetic similarities, inhabiting a certain range in nature, capable of interbreeding and giving while prolific offspring. ”We can put it another way:

- “species - a set of geographically and ecologically similar populations that are capable of interbreeding under natural conditions, having common morphophysiological characteristics, biologically isolated from populations of other species”;

- “a species is a collection of individuals living in a specific area, having common morphophysiological characters, freely interbreeding, and representing stable genetic systems”;

- “A species is a collection of individuals with similar morphological and physiological characteristics. Able to cross with the formation of prolific offspring. They inhabit a certain area, having a common origin and similar behavior. ”

The keywords in the definition are a group of individuals with similarities; able to interbreed with each other and produce prolific offspring. If organisms belong to different species, they usually do not interbreed (the border between different species). Sometimes different species can be very well identified by external signs (polar and brown bear). There are cases when a female and a male, belonging to the same species, differ in appearance (sexual dimorphism). For the reliability of the separation of organisms into species, a combination of characteristics or criteria is used. Then, in the process of a frontal conversation with students, a table is filled in (the material was studied in grade 9, so we rely on the students' knowledge).

Conclusion: what criterion do we rely on when determining the species? (on a set of criteria). By structure, species are divided into monotypic and polytypic (with a well-defined structure). In the latter, subspecies, ecotypes, and populations are distinguished.

Determination of the criteria of the species (fixing material) -10min

I invite students to determine what criteria the text says:

Hippopotamus or hippo.

The sizes are very large: in adult males, the body length is up to 4.5 m, weight up to 3.2 tons (morphological). The skin contains many glands that secrete a mucous secretion that protects the skin from drying out in the air. The secret has a reddish color, so live animals are pinkish in color (biochemical). Hippos sleep during the day in shallow water or near water, graze at night in coastal meadows, rarely moving away from the water (ecological). Maturity occurs in males at 9 years old, in females at 7 years old. The mating period happens twice a year: in February and August. Pregnancy lasts 240 days, childbirth occurs in water (physiological).

Common squirrel.

The head is rounded with large black eyes, ears are long, at the ends with tassels, especially developed in winter. Body length 20-28 cm, tail length 13-19 cm. Fur is soft and fluffy in winter, stiffer in summer, shorter (morphological). Squirrel is distributed in the forest zone of Eurasia from the coast of the Atlantic to the coastal islands of the Western Pacific (Sakhalin, the northern part of the Japanese Islands) - geographical. A characteristic inhabitant of coniferous and deciduous forests. It prefers closed tall, mature stands of mixed composition: spruce-cedar-larch (ecological). In deciduous forests, it usually lives in hollows; in conifers, it builds spherical nests from branches - “Guyna”, lining the internal cavity with moss, bast, lichens and dry plant rags (ecological). Reproduction begins in January-February and ends in July-August. During this time, the female brings 2 broods. Pregnancy lasts 35-40 days, in a brood from 2-3 to 8-11 squirrels (physiological). One of the main commercial species.

Central Asian cobra.

Cobras are very dangerous animals with a potent poison of a neurotoxic effect. Cobra venom depresses the central nervous system and leads to paralysis of the respiratory center (biochemical). This is a large snake about 2 m long, painted in a variety of colors - from light olive to almost black (morphological). In Turkmenistan, cobra is most often found in hilly foothills and wide stony intermontane depressions covered with grassy vegetation (ecological). They hibernate in deep burrows of gerbils at a depth of 1 - 1.2 m, 1 - 2 specimens in one shelter. Wintering lasts 140 - 150 days (physiological). From the venom of cobra the preparation "Kobrotoxin" is prepared, which is used to treat bronchial asthma and some forms of cancer.

Hanging or warty birch.

A slender tree up to 20 m high, with an openwork crown and drooping thin branches. The bark is snowy white, exfoliating with thin plates (morphological). It blooms in late April - early May; seeds ripen in late August-September (physiological). Distributed in Russia in the forest and forest-steppe zone of the European part and Western Siberia (geographical). It forms vast clean forests, populating disturbed habitats: cutting areas, conflagration, abandoned arable land, and also grows in a mixture with other species, especially often with pine and spruce. Birch is used in medicine and perfumery, in construction.

5. Summarizing the lesson. Grading, homework (p. 12) - 2 min

Goals and objectives of the lesson: to form the concept of "species", "criteria of the species", "population"; continue to develop the skills of working with texts, tables; ability to analyze, draw conclusions.

During the classes

1. Organizational moment

Formulation of the topic of the lesson. Setting goals and objectives of the lesson

2. Repetition of the material covered (establishing the relationship of previously studied material and material of a new topic)

a) The concept of the species K. Linnaeus, J.B. Lamarck and C. Darwin (checking the correctness of the answers on slides 2-4)

b) Who proposed the binary nomenclature of the species?

c) What does the double name include? Give examples

Find in the textbook a modern definition of the species (for verifying sl. 5)

Why do you think the modern definition of a species is so complicated?

(avoid mistakes in determining the belonging of individuals to one species)

Teacher Supplement: Linnaeus made a mistake by referring the male and female mallard ducks to different species, taking into account only external signs (Sl.6)

3.Study of new material

a) The teacher’s story about what the species is and what are the criteria for the species using the presentation, the concept of reproductive isolation, its causes and significance for the existence of the species is given (Sl. 7-22)

Class assignment:

In the course of explanation and viewing v / f fill in the table

b) Viewing a video fragment from the educational film “View Criteria”, where specific examples of view criteria and their relativity are given.

c) Independent work of students to make additions to the table after watching a video fragment

d) Verification of the basic concepts entered in the table

d) Formulation of conclusions (vl. 23, 25)

4. Fastening (vl. 24-26)

5. The concept of "Population" (vl. 28-31)

6. Summarizing the lesson, setting grades.

7. Homework: par 1.4.1, questions 1-5, table,

Additional questions for homework.

1. Two cultivated plants barley and rye have the same set of chromosomes (14), but do not interbreed, differ in appearance and chemical composition. Define: a) Barley and rye should be referred to one or different types. b) What criteria specified in the text should be guided by?

2. Two breeds of rabbits have the same number of chromosomes (44), but do not cross. differ in appearance and puberty. a) Should one or different species include these breeds of rabbits? b) What criteria specified in the text should be guided by?

References.

1. Textbook "Biology" VBZakharov, S.G. Mamontov, V.I. Sivoglazov 11 cl.
2. G. Murtazin "Tasks and exercises in general biology"
3. N.A. Lemez, L.V. Kamnyuk, N.D. Lisov "Biology manual for applicants to universities"
4. UNESCO Courier Magazine June 1982
5. Internet Pictures