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Goals:

• educational– expand, generalize and deepen knowledge about the main driving forces of evolution - the struggle for existence and natural selection; reveal the relationships between organisms within a population, between organisms of different species, the relationships of organisms with factors of inanimate nature.
• developing– develop students’ cognitive interest, the ability to work with a textbook, tables, slides, draw conclusions, and be able to use previously studied material.
• educational- cultivate interest in biology lessons, caring for the nature around us.

Methodological goal: the use of ICT as one of the ways to form creative thinking and develop students’ interest, expand the experience of research activities based on previously acquired knowledge, develop information and communication competencies.

Lesson type: combined.

Lesson type: lesson in the formation and systematization of knowledge.

Method of conducting: dialogue based on working with textbook materials, tables, slides.

Level of knowledge acquisition: partially search.

Interdisciplinary connections: biology, ecology, geography, literature.

Educational and methodological support:

• General biology: a textbook for students. education institutions of secondary prof. education ed. V.M. Konstantinova,
• textbook “General biology 10-11 grades.” D.K. Belyaev, table “The struggle for existence and its forms”, presentation on the topic: “Natural selection is the main driving force of evolution.”

Logistics: teacher's workplace, laptop, projector, screen, student workplaces.

Lesson progress

Lesson steps	Teacher's activities	Student activities
1. Org. moment.	Checking the list of students. Bring to students the goals and objectives of the lesson.	Report.
2. Checking previously studied material.	Frontal survey on the topic: “Struggle for existence.” 1) Explain the terms: (Slide No. 4-6) Struggle for existence. Intraspecific struggle for existence. Interspecies struggle for existence. Combating unfavorable environmental conditions. 2) Find the relationship between the pictures and concepts. (Slide No. 7)	Reflection of students' knowledge on the topic and answers to the proposed questions.
	3) Give answers to the questions: (Slide No. 8-9) What is the meaning of the struggle for existence? What is the result of the struggle for existence? What do you think natural selection is? How do adapted individuals arise? Which variability is more important? Thus, the basis for the success of evolution is the diversity of organisms. 4) At the same time, three students complete an individual task (the task is given on separate sheets).	Complete the task. They look at the slides. Fill out the table. Answer questions.
3. Studying new material.	Lesson plan: (slide number 3 on screen) The concept of “natural selection”. Forms of natural selection. The creative role of natural selection. Sexual selection as a stabilizing form of natural selection. Comparison of natural and artificial selection. Presentation of new material, dialogue with students through a system of problematic questions, using slide presentations. When considering new lesson material, students complete tasks on the control sheet (Appendix 2). Tasks No. 5 and No. 6 on the control sheet can be recommended as homework.	Work in notebooks on a lesson plan.
	Natural selection always acts as the main factor in the transformation of living organisms. Its mechanism of action is the same, i.e. Natural selection each time promotes the survival and leaving of offspring of the fittest individuals. (slide number 10). Natural selection is a process as a result of which the most fit individuals of each species preferentially survive and leave offspring and the less fit ones die. Here are the selection characteristics: (slide No. 11-12).	Perception and partial understanding of new things by students.
	1. A necessary prerequisite is hereditary variability; 2. Character - directional, it is always directed towards greater adaptability to environmental conditions; 3. Selection factor – natural environment with its own conditions; 4. Genetic essence - consists in the non-random preservation of certain genotypes in the population and their selective participation in the transmission of genes to the next generation; 5. The result is the transformation of the gene pool of the population, the formation of adaptations; 6. The consequence is an increase in the diversity of forms of organisms; consistent complication of organization in the course of progressive evolution; extinction of less adapted species. Thus, natural selection is capable of purposefully selecting from generation to generation individuals that are more adapted to environmental conditions (slide No. 13).	Answer questions with reasons for their answer. (Why do you think so?) Participate in dialogue with the teacher and make the necessary notes.
	Let's consider the mechanism of natural selection (slide No. 14-15). Natural selection is revealed quite fully only in fairly large populations, since as the population decreases, the role of random factors increases. However, depending on its focus, effectiveness and characteristics of the living conditions of organisms, the forms of natural selection can be different (slide No. 16). Let's give them a description.	Offer their answers with justification. They write it down.
	Driving (directed, leading) selection (slide no. 17-18) - a form of selection that favors only one direction of variability and does not favor all its other variants. Under the control of driving selection, the gene pool of the population changes as a whole, that is, there is no separation of daughter forms (divergence). Mutations accumulate and spread in the gene pool of a population, ensuring a change in the phenotype in a given direction. In a population, under the influence of driving selection, a trait changes from generation to generation in a certain direction.	Working with textbook material on page 147. Perception and comprehension of new material.
	Let us give examples of the action of driving selection (slide no. 19-20) A classic example of driving selection is the evolution of color in the birch moth. The color of the wings of this butterfly imitates the color of the lichen-covered bark of trees on which it spends the daylight hours. Obviously, such a protective coloration was formed over many generations of previous evolution. However, with the beginning of the industrial revolution in England, this device began to lose its importance. Atmospheric pollution has led to massive death of lichens and darkening of tree trunks. Light butterflies against a dark background became easily visible to birds. Beginning in the mid-19th century, mutant dark (melanistic) forms of butterflies began to appear in birch moth populations. Their frequency increased rapidly. By the end of the 19th century, some urban populations of the birch moth consisted almost entirely of dark forms, while rural populations continued to be dominated by light forms. This phenomenon was called industrial melanism. Scientists have found that in polluted areas, birds are more likely to eat light-colored forms, and in clean areas, dark ones. The introduction of air pollution restrictions in the 1950s caused natural selection to reverse course again, and the frequency of dark forms in urban populations began to decline.	Working with terminology. They take part in the dialogue, ask questions, and make the necessary notes.
	- Increase in body size in a horse (phylogenetic series of the horse). Development of resistance to pesticides (in rats). Stabilizing selection. (slide No. 21-22) Stabilizing selection preserves the state of the population that ensures its maximum fitness under constant conditions of existence. Provides phenotypic invariance of species. In each generation, individuals that deviate from the average optimal value for adaptive traits are removed. Selection pressure is directed towards organisms with an average expression of the trait. As a result, it is protected from the destructive effects of the mutation process. Many examples of the action of stabilizing selection in nature have been described. For example, at first glance, it seems that the greatest contribution to the gene pool of the next generation should be made by individuals with maximum fertility. However, observations of natural populations of birds and mammals show that this is not the case. The more chicks or cubs in the nest, the more difficult it is to feed them, the smaller and weaker each of them is. As a result, individuals with average fertility are the most fit. Selection toward the mean has been found for a variety of traits. In mammals, very low- and very-high-weight newborns are more likely to die at birth or in the first weeks of life than average-weight newborns. A study of the size of the wings of birds that died after the storm showed that most of them had wings that were too small or too large. And in this case, the average individuals turned out to be the most adapted. (slide No. 23-25) Examples of stabilizing selection are the preservation of flower size and shape in insect-pollinated plants, since flowers must correspond to the body size of the pollinating insect, or the preservation of relict species (hatteria, coelacanth, ginkgo, etc.)	They work with slide materials, drawing certain conclusions.
	Conclusion: the driving and stabilizing forms of natural selection are closely related to each other. Disruptive or disruptive selection. (slide No. 28)	They work with the materials from slides No. 26-27 “Comparison of selection forms”, drawing certain conclusions.
	Occurs when different environmental conditions exist in different parts of the range of a given species, or population. This form of selection favors two or more directions of variation (classes of phenotypes), but does not favor the average (intermediate phenotype). Under the influence of discontinuous selection, polymorphism usually arises within a population—several distinctly different phenotypic forms. The action of disruptive selection within a species leads to the isolation of populations from each other, up to their isolation as new species. Let's look at examples of a disruptive form of natural selection (slide No. 29-32). Among some bird species (skuas, cuckoos, falcons, etc.) color forms are common. Sexual dimorphism (difference in appearance between males and females, for example, stag beetles, lions, Galliformes, etc.) is a special case of polymorphism. The polymorphism of some species of snails makes it possible for them to exist on different types of soils. In the created conditions, selection begins to operate for each of the forms, aimed at their stabilization.	They draw their own conclusions. Take part in the dialogue and make the necessary notes.
	Sexual selection (slide No. 33-37) Sexual selection is a form of natural selection in some species of animals, based on the competition of one sex for mating with individuals of the other sex. Due to sexual selection appeared sexual dimorphism and developed secondary sexual characteristics(bright plumage, branched antlers, etc.) These signs can be harmful both for the individual and for the species (for example, heavy branched antlers in deer, heavy bright tail in some birds). Why, then, does selection preserve and often aggravate these traits?	They take part in the dialogue and draw their own conclusions.
4. Consolidation of the studied material.	Summarizing conversation while learning new material. Complete the tasks of the control and generalization test. (slide no. 39-40) Giving grades to students for their work in class. If there is time left in the lesson, then we work with the table “Comparison of artificial and natural selection” (slide No. 42-43) When leaving the lesson, I ask you all to reflect your attitude towards the lesson by placing a sign in the column of the table that corresponds to your mood. Interesting Not interested Doesn't matter	Demonstration of knowledge acquired in the lesson. They take part in the dialogue and draw their own conclusions. Work with slide presentation materials. Summing up the lesson. Reflection of interest in the material studied. Leave notes on the survey sheet.
5. D\z (2 min).	Paragraph 3.4, pp. 136 – 139 textbook for students. education institutions of the environment prof. Education “General Biology” V.M. Konstantinov. Paragraph 47, pp. 166 – 169 textbook “General Biology” D.K. Belyaeva. Fill out the table “Comparative characteristics of artificial and natural selection”	Write down d\z. (Slide No. 32)

List of literature for students

List of literature for the teacher

1. General biology: a textbook for students. education institutions of secondary prof. education / V.M. Konstantinov, A.G. Rezanov, E.O. Fadeeva; edited by V.M. Konstantinova.- M.: Publishing Center “Academy”, 2010.

2. General biology: Textbook. For 10-11 grades. general education institutions/ D.K. Belyaev, P.M. Borodin, N.N. Vorontsov and others; Ed. D.K. Belyaeva, G.M. Dymshitsa. – M.: Education, 2004. – 304 p.

3. Lerner G.I. Biology lessons. General biology. 10th, 11th grades. Tests, questions, tasks: Study guide. – M.: Eksmo, 2005. – 352 p.

4. I.F. Ishkina Biology. Lesson plans. 11th grade / Ed. D.K. Belyaeva, A.O. Ruvinsky. – Volgograd, 2002. – 120 p.

5. Petunin O.V. Biology lessons in 11th grade. Detailed planning - Yaroslavl: Development Academy, Academy Holding, 2003. - 304 p.

When preparing the presentation we used information resources:

12. “Black form” of the two-spot ladybug

The founders of the modern (synthetic) theory of evolution THE FOUNDERS OF MODERN
(SYNTHETIC) THEORY OF EVOLUTION
Fundamentals of the doctrine of
natural selection were
laid down by Charles Darwin in his
works on the theory of evolution
(Darwinism). Concept of
natural selection
has expanded significantly and
deepened thanks to
development of genetics, works
I.I. Shmalhausen and S.S.
Chetverikova.

SERGEY SERGEEVICH CHETVERIKOV
(1882 – 1959)
DOMESTIC SCIENTIST, EVOLUTIONIST AND GENETICIST.
HIS WORK GAVE THE BEGINNING TO MODERN SYNTHESIS
GENETICS AND DARWINISM.
IVAN IVANOVICH SHMALGAUZEN
(1884 – 1963)
ACADEMICIAN, ONE OF THE LARGEST THEORISTS
EVOLUTIONARY TEACHING

Modern ideas about natural selection

MODERN PERSPECTIVES ABOUT
NATURAL SELECTION
Natural selection is a process in which
as a result of which they survive and
individuals leave offspring with
useful in these conditions
hereditary characteristics.
The selection may include
both individuals and whole
populations. In any case, the selection
preserves the fittest
to these conditions of existence
organisms. Natural factors
selection is served by external conditions
environment; depending on these conditions
selection operates in different
directions and leads to
unequal evolutionary
results.

The concept of “natural selection”

Selective survival and
reproduction most
adapted organisms
(C. Darwin)
The process, as a result
which is predominantly
survive and leave
offspring most
adapted individuals and
die less
adapted
(modern definition)

Forms of natural
selection
Stabilizing
(stable conditions
environment)
Moving
(changing
environmental conditions)
Disruptive
(changing
environmental conditions)
Survive and
individuals reproduce from
average manifestation
sign
Survive and
individuals reproduce with
one of the extreme
characteristic deviations
Survive and
individuals reproduce from
all extreme
deviations of the characteristic
Examples: compliance
flower structure and
pollinating insect,
"living fossils".
Examples:
industrial
birch melanism
moths, stability
pests to
pesticides
Examples:
polymorphism,
wingless and
long-winged birds
oceanic islands

Stabilizing selection

STABILIZING SELECTION
Aimed at conservation
established in the population at
constant medium environmental conditions
characteristic values ​​result
actions of stabilizing selection
is the great similarity of all individuals
plants or animals observed
in any population. This form
natural selection protects
established genotype from
destructive effect of mutation
process.

number of individuals
trait variability

Driving selection

DRIVING SELECTION
Motive form of natural
selection contributes to a shift in the mean
attribute or property values ​​and
leads to the emergence of new
the average norm instead of the old one.
For example, in natural ecosystems
Light-colored ones mostly survive
birch moth shape,
invisible on tree trunks.
However, in areas with intense
industrial pollution
gets the advantage
dark-colored form, good
camouflages on contaminated
soot on birch tree trunks.

number of individuals
trait variability

Destabilizing selection

DESTABILIZING SELECTION
Studied D.K.
Belyaev, D.
Simpson, N.
Vorontsov
Occurs in
heterogeneous
environment
Norm of reaction
is expanding,
advantages
individuals receive from
mutations with more
broad rule
reactions

Destabilizing selection

DESTABILIZING SELECTION
Lake populations
frogs living in
ponds with heterogeneous
illumination, with
alternating sections,
overgrown with duckweed,
reeds, cattails, with
“windows” of open water –
resulting in a wide
range of variability
coloring

Disruptive form of selection

OBSERVED WHEN
IN DIFFERENT PARTS OF THE AREA
VARIOUS WORK
ENVIRONMENTAL CONDITIONS.
WITHIN A POPULATION
SEVERAL ARISES
CLEARLY DIFFERENT
PHENOTYPICAL FORMS.

Disruptive selection

DISRUPTIVE SELECTION
Kiwi bird.
Burevesnik
Wingless
there was a great auk
exterminated in
mid 19
century.

number of individuals
trait variability

Other forms of natural selection SEXUAL SELECTION

THIS IS A SPECIAL CASE OF NATURAL SELECTION IN SOME SPECIES
ANIMALS BASED ON COMPETITION OF THE SAME SEX FOR
MATING WITH OTHERS.
DUE TO IT, SEXUAL DIMORPHISM APPEARED AND DEVELOPED
SECONDARY SEXUAL CHARACTERISTICS.
MALES CAN COMPETE DIRECTLY WITH EACH OTHER –
INTRASEXUAL SELECTION
Males can compete indirectly by attracting females
displays and decorations – intersexual selection

intraspecific and interspecific selection

INTRASPECIES AND INTERSPECIES SELECTION

Other forms of natural selection

OTHER FORMS OF NATURAL SELECTION
1.
2.
Individual selection
Comes down to
preferential
reproduction of individual
individuals with
genotypes,
ensuring success in
struggle for existence in
within the population
Any signs and
properties of species and more
large systematic
groups are formed in
the process of selecting individuals for
basis for assessing them
individual differences
1.
2.
3.
Group (mass)
selection
Selective breeding
any group of individuals,
entered into direct or
indirect relationships
The signs are fixed
favorable for the group as a whole
May lead to displacement
one of the competing groups and
contribute to or reduce
species diversity, or
emergence of new differences
between forms

THE CREATIVE ROLE OF NATURAL SELECTION IS MANIFESTED IN THE fact that, ACTING FOR MILLIONS AND BILLIONS OF YEARS, IT TOGETHER WITH OTHER FACTORS

EVOLUTION CREATED EVERYTHING HUGE
DIVERSITY OF SPECIES IN NATURE, ADAPTABLE TO LIFE.

Comparison of natural and artificial selection fill out the table

Indicators
Artificial selection
Natural selection
(directed -
non-directional)
(directed -
non-directional)
Source material for
selection
Selective factor
Path of the auspicious
changes
The path of unfavorable
changes
Nature of action
Duration
Selection result
Selection forms
Mass,
individual

Task: match

TASK: match
Selection characteristics:
1.
Individuals with
established norm
trait reactions.
2.
Individuals with all
forms of deviations from the norm
trait reactions.
3.
Individuals with one of the
deviations from the norm of reaction
sign
4.
Manifests itself in constant
environmental conditions
5.
Appears in new conditions
environment.
6.
Does not affect evolutionary
process.
7.
Affects
evolutionary process.
A – driving selection
B – stabilizing selection
B – disruptive selection

Answers

ANSWERS
A) 3, 5, 7.
B) 1, 4, 6.
B) 2, 5, 7.

Homework

HOMEWORK
11th grade.
1. Read §58 (grade 11), §7.5 (grade 9).
2. Answer the questions orally at the end
paragraph.
3. Learn the concepts in bold
font.

Driving selection The driving form contributes to a shift in the average value of a trait or property and leads to a new average norm instead of the old one, which no longer corresponds to new conditions. The driving form contributes to a shift in the average value of a characteristic or property and leads to a new average norm instead of the old one, which no longer corresponds to new conditions. Operates when environmental conditions change. Operates when environmental conditions change.

Thus, the leading role in the spread of new characteristics within a species when environmental conditions change belongs to the driving form of natural selection. Changes in symptoms can occur both in the direction of its intensification, greater severity, and in the direction of weakening until complete disappearance.

The role of selection in nature is not limited to the elimination of individual traits that reduce viability or competitiveness. The role of selection in nature is not limited to the elimination of individual traits that reduce viability or competitiveness. In reality, in nature, selection preserves not individual traits, but entire phenotypes, i.e. the whole complex of characteristics, and therefore certain combinations of genes inherent in a given organism. In reality, in nature, selection preserves not individual traits, but entire phenotypes, i.e. the whole complex of characteristics, and therefore certain combinations of genes inherent in a given organism.

Stabilizing selection Operates under constant environmental conditions. Operates in constant environmental conditions. Aimed at maintaining a previously established average trait or property: the size of the body or its individual parts in animals, the size and shape of a flower in plants, etc. Aimed at maintaining a previously established average trait or property: the size of the body or its individual parts in animals, the size and shape of a flower in plants, etc.

A stabilizing type of selection preserves the fitness of the species by eliminating sharp deviations in the expression of a trait from the average norm. A stabilizing type of selection preserves the fitness of the species by eliminating sharp deviations in the expression of a trait from the average norm. Genes that cause deviations from the norm are eliminated from the gene pool of the species. Genes that cause deviations from the norm are eliminated from the gene pool of the species. The stabilizing form of natural selection protects the existing genotype from the destructive effects of the mutation process. The stabilizing form of natural selection protects the existing genotype from the destructive effects of the mutation process.

Sexual selection is the competition between males for the opportunity to reproduce. Sexual selection is the competition between males for the opportunity to reproduce. This form of selection should be considered a special case of intraspecific natural selection. This form of selection should be considered a special case of intraspecific natural selection.

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Presentation - Natural selection is the main driving force of evolution

Text of this presentation

Natural selection is the main driving force of evolution.

GOALS
Develop concepts about various forms of natural selection. To formulate in students the ability to compare different forms of natural selection with each other and correctly identify them by their essential characteristics. To consolidate knowledge about natural selection - as the main and guiding driving force of the evolutionary process.

LESSON PLAN
The concept of "natural selection". Forms of natural selection. The creative role of natural selection. Sexual selection as a stabilizing form of natural selection. Comparison of natural and artificial selection.

EXPLAIN THE TERMS
Struggle for existence. Intraspecific struggle for existence. Interspecies struggle for existence. Combating unfavorable environmental conditions.

Intraspecific
Interspecific
Competition for water and food sources
Competition for nesting sites in birds
Displacement of one species by another from its habitat
Relationship between predator and prey
Struggle for existence

- These are complex and diverse relationships between individuals within species, between species and environmental conditions.
Struggle for existence
Intraspecific struggle occurs between individuals of the same species. This is the toughest and sharpest of all types. Competition between predators for prey, competition for territory, for a female, for living space, for breeding sites. Interspecific struggle leads to the evolution of both interacting species and to the development of mutual adaptations in them. Strengthens and aggravates intraspecific struggle. This is the unilateral use of one species by another. In the fight against unfavorable environmental conditions, the winners are the most viable individuals (with effective metabolism and physiological processes). These are plants and animals of the deserts and the far north.

Find relationships between concepts and pictures
Intraspecific struggle, interspecific struggle, struggle with unfavorable environmental conditions.
A)
B)
IN)
G)
D)
E)
AND)

GIVE ANSWERS TO QUESTIONS
1. What is the meaning of the struggle for existence?
- in the formation of fitness in organisms.
2. What is the result of the struggle for existence?
- natural selection.
3. What do you think natural selection is?
Natural selection –
survival of the fittest organisms.

GIVE ANSWERS TO QUESTIONS
4. How do adapted individuals arise?
- as a result of the action of the struggle for existence and natural selection.
5. Which variability is more important?
- hereditary variability.
The basis for the success of evolution is the diversity of organisms.

This is the selective survival and reproduction of the most adapted organisms (C. Darwin)
NATURAL SELECTION
Charles Robert Darwin (English: Charles Robert Darwin; 1809-1882) - English naturalist and traveler.
a process as a result of which the most fit individuals of each species preferentially survive and leave offspring and the least fit ones die

3. Selection factor
Natural environment with its own conditions

1.Necessary prerequisite
Hereditary variability
2.Character
Directional (always directed towards greater adaptability to the environment)

6. Consequence
Increasing the diversity of forms of organisms; consistent complication of organization in the course of progressive evolution; extinction of less adapted species
4.Genetic essence
Non-random preservation of certain genotypes in a population and their selective participation in the transmission of genes to the next generation
5.Result
Transformation of the population gene pool, formation of adaptations
CHARACTERISTICS OF NATURAL SELECTION

Natural selection is capable of purposefully selecting from generation to generation individuals that are more adapted to environmental conditions. By selecting useful traits, natural selection creates new species.
THE CREATIVE ROLE OF NATURAL SELECTION

NATURAL SELECTION
Reason: struggle for existence. Material: hereditary variability Efficiency: the more different mutations in a population (the higher the heterozygosity of the population), the greater the efficiency of natural selection, the faster evolution proceeds.

MECHANISM OF EVOLUTION (according to the theory of Charles Darwin)
Evolution is the process of historical development of living nature based on variability, heredity and natural selection.

Hereditary variability (mutations, combinative variability)
Heterogeneity of the population (the appearance of individuals with a variety of characteristics)
The struggle for existence (in its various manifestations)
“Defeat” of the least adapted individuals with unfavorable characteristics
“Victory” of the fittest individuals with important favorable characteristics
Selective elimination
They have no chance of procreation
Elimination from reproduction
Unfavorable traits are not passed on to offspring
Survival and preferential participation in reproduction
Favorable traits are passed on to descendants
NATURAL SELECTION

FORMS OF NATURAL SELECTION

DRIVING SELECTION
A
B
IN
G
A-D – successive changes in the reaction norm under the pressure of the driving force of natural selection
Selection pressure

DRIVING SELECTION
Leads to the destruction of individuals with the old norm of reaction and the formation of a population of individuals with new characteristics. It takes place in slowly changing environmental conditions. The resulting hereditary changes are beneficial.

Industrial melanism is variability caused by intensive industrial development and environmental deterioration.
Industrial melanism in the birch moth butterfly
The butterflies living on the trunks of birch trees were light in color. Among them, dark-colored forms appeared from time to time, which were destroyed by birds. Due to the development of industry and air pollution, the trunks of birch trees have acquired a grayish tint. As a result, light-colored butterflies were destroyed by birds, while dark-colored ones were preserved. After some time, all butterflies in the population became dark-colored.

DRIVING SELECTION
Increasing horse body size
Phylogenetic series of the horse
Development of resistance to pesticides
Transforms species under changing environmental conditions. Provides a wide distribution of life, its penetration into all possible ecological niches. Under stable conditions of existence, natural selection does not cease, but continues to act in the form of stabilizing selection.

STABILIZING SELECTION
There is a narrowing of the reaction norm.
Initial variability of traits.
Selection pressure
Selection pressure

In slightly variable (constant) environmental conditions, the number of individuals with an average reaction rate increases. From generation to generation, extreme forms are cut off, and organisms with a certain reaction norm are fixed (preservation of the average phenotypic norm)
STABILIZING SELECTION

Hatteria
STABILIZING SELECTION
Preserves individuals with the norm of reaction established under given conditions and eliminates all deviations from it. Operates in environmental conditions that do not change for a long time.
Relic species

GINKGO (Ginkgo biloba), the only surviving species of the vast order Ginkgoidae, which flourished during the Mesozoic era. The only modern representative is G. biloba (G. biloba) - a tree 30-40 m high, up to 1 m thick, with a spreading crown; dioecious. Found in few areas of East Asia. The plant's name means "silver apricot" in Japanese.
STABILIZING SELECTION
Relic species

The flowers of snapdragon plants are pollinated by bumblebees. The size of the flowers corresponds to the body size of bumblebees. All plants that have flowers that are too large or too small are not pollinated and do not form seeds, that is, they are eliminated by stabilizing selection.
STABILIZING SELECTION
Snapdragon.

COMPARISON OF SELECTION FORMS
STABILIZING MOVING
1. Constancy of the external environment 1. Changes in environmental conditions
2. Neutralization of mutations by selecting combinations in which their harmful effects are neutralized 2. Opening up the stock of variability
3.Improving the genotype with a constant phenotype. 3. Selection of neutralizing mutations and their combinations
4. Formation of a mobilization reserve of hereditary variability 4. Formation of new genotypes and phenotypes

STABILIZING MOVING
By sweeping away deviations from the norm, it actively forms genetic mechanisms that ensure the stable development of organisms and the formation of optimal phenotypes based on various genotypes. It ensures the stable functioning of organisms in a wide range of fluctuations in external conditions familiar to the species. Plays a decisive role in the adaptation of living organisms to changing external conditions over time. Ensures the wide distribution of life, its penetration into all possible ecological niches. Under stable conditions of existence, natural selection continues to act in the form of stabilizing selection.
COMPARISON OF SELECTION FORMS

There is a gap in the reaction norm (individuals with an average value are displaced)
Selection pressure

The timing of flowering and seed ripening in the meadow rattle extends throughout almost the entire summer, with most of the plants blooming and bearing fruit in mid-summer. In hay meadows, those plants that have time to flower and produce seeds before mowing, and those that produce seeds at the end of summer, after mowing, benefit. As a result, two races of rattle are formed - early and late flowering.
DISRUPTIVE SELECTION (disruptive)
A type of natural selection in a population of animals or plants that leads to the emergence of two or more new forms from one original one.

For example, in the absence of food necessary for the growing juvenile perches, i.e., fry of other fish, only “dwarfs” (individuals with sharply slow growth, which can feed on planktonic crustaceans for a long time) and “giants” (individuals capable of already by the end of the first year of life they eat perch fry of their own generation). In such a situation in a reservoir for a number of years, as a result of D. o. Hereditary races of “giants” and “dwarfs” will be formed.
Sometimes environmental conditions change sharply, in such a way that extreme forms gain advantage. The number of extreme forms is rapidly increasing, which, with the participation of isolation, can lead to a transformation of the species. This selection is directed against intermediate forms.
DISRUPTIVE SELECTION (disruptive)

DISRUPTIVE SELECTION (disruptive)
The case of the predominant survival of “red” forms of the two-spotted ladybug in the winter season and “black” forms of the two-spotted ladybug in the summer season has been well studied.
This form of selection occurs when two or more genetically different forms have an advantage under different conditions, such as different seasons of the year.

NATURAL SELECTION
OPERATES FROM OUTSIDE STRENGTHENS ADAPTABILITY
ACTS FROM INSIDE IN TWO OR MORE DIRECTIONS
ONLY ACTS IN ONE DIRECTION
STABILIZING
MOVING
TEARING
TWO OR MORE NEW SIGNIFICANCE STANDARDS ARE FORMED
THE NORM OF THE CHARACTER DOES NOT CHANGE, BUT THE NUMBER OF INDIVIDUALS INCREASES
THE NORM OF A CHARACTER CHANGES

a form of natural selection in some animal species based on competition of one sex for mating with individuals of the other sex.
Polymorphism
Secondary sexual characteristics are a set of features or characteristics that distinguish one sex from another (with the exception of the gonads, which are primary sexual characteristics).
SEXUAL SELECTION
Sexual dimorphism
“This form of selection is determined not by the struggle for existence in the relations of organic beings among themselves or with external conditions, but by the competition between individuals of one sex, usually males, for the possession of individuals of the other sex.” (C. Darwin)

POLYMORPHISM
Polymorphism is the existence within one species of several clearly morphologically different forms.
Polymorphism in dioecious animals is the presence of individuals of different appearance within the same sex.

POLYMORPHISM

POLYMORPHISM
Seasonal polymorphism is a type of ecological polymorphism. The appearance of the insect depends on the season.
In the population of moth butterflies, the generations that appear in the spring are distinguished by the reddish-red color of their wings with a characteristic arrangement of dark spots. At the same time, the summer generation consists of individuals with brown wings. This phenomenon is due to the fact that in spring, at lower temperatures, the butterfly’s body produces less dark pigment, which is responsible for the color of the wings.

POLYMORPHISM
In social insects, sexual polymorphism is observed, associated with the division of functions of different individuals in a family or colony (for example, the queen and workers in bees).

1. The starting material for natural selection is A) the struggle for existence B) mutational variability C) changes in the habitat of organisms D) the adaptability of organisms to the environment 2. Charles Darwin’s evolutionary theory is based on the doctrine of A) divergence B) natural selection C ) degeneration D) artificial selection 3. Selection, as a result of which individuals with an average manifestation of a trait are preserved, and individuals with deviations from the norm are discarded, is called A) driving B) methodical C) spontaneous D) stabilizing 4. The creative nature of natural selection is manifested in evolution in A) increased competition between species B) weakened competition between populations C) increased competition between individuals of the same species D) the emergence of new species 5. The effectiveness of natural selection decreases with A) increased intraspecific struggle B) changes in the reaction norm C) weakening of the mutation process D) strengthening the mutation process
Generalization test

6. What does the strengthening of the mutation process in a natural population lead to? A) increasing the efficiency of natural selection B) increasing the intensity of the cycle of substances C) increasing the number of individuals D) improving self-regulation 7. The action of natural selection leads to A) mutational variability B) preservation of traits useful for humans C) random crossing D) the emergence of new species 8. The result of evolution is A) hereditary variability B) struggle for existence C) diversity of species D) aromorphosis 9. Thanks to what form of selection have lobe-finned fish been preserved in nature? A) methodical B) driving C) stabilizing D) breaking 10. The main result of evolution is A) the adaptation of organisms to the environment B) fluctuations in population numbers C) a decrease in the number of populations of a species D) the struggle for existence between individuals of the same species
Generalization test

Answers to the generalization test
1 2 3 4 5 6 7 8 9 10
B B G G V A G V V A

Source material for selection
Selective factor
The path of favorable changes
The Path of Unfavorable Change
Nature of action
Selection result
Selection forms

Indicators Artificial selection Natural selection
Source material for selection Individual characteristics of an organism Individual characteristics of an organism
Selecting factor Human Environmental conditions
Path of favorable changes Selected, become productive Remain, accumulate, passed on by inheritance
The path of unfavorable changes Selected, rejected, destroyed Destroyed in the struggle for existence
Nature of action Creative - directed accumulation of traits for the benefit of man Creative - selection of adapted traits for the benefit of an individual, population, species, leading to the emergence of new forms
Result of selection New varieties of plants, breeds of animals, strains of microorganisms New species
Forms of selection Mass, individual, unconscious, methodical Driving, stabilizing, disruptive, sexual

HOMEWORK
§3.4, pp. 136 – 139 textbook for students. education institutions of the environment prof. education “General Biology” V.M. Konstantinov. § 47, pp. 166 – 169 textbook “General Biology” D.K. Belyaeva. Fill out the table “Comparative characteristics of artificial and natural selection”

Thank you for your attention!

General biology: a textbook for students. education institutions of secondary prof. education / V.M. Konstantinov, A.G. Rezanov, E.O. Fadeeva; edited by V.M. Konstantinova.- M.: Publishing center "Academy", 2010. General biology: Textbook. For 10-11 grades. general education institutions/ D.K. Belyaev, P.M. Borodin, N.N. Vorontsov and others; Ed. D.K. Belyaeva, G.M. Dymshitsa. – M.: Education, 2005. – 304 p. Lerner G.I. Biology lessons. General biology. 10th, 11th grades. Tests, questions, tasks: Study guide. – M.: Eksmo, 2005. – 352 p. I.F. Ishkina Biology. Lesson plans. 11th grade / Ed. D.K. Belyaeva, A.O. Ruvinsky. – Volgograd, 2002. – 120 p. Petunin O.V. Biology lessons in 11th grade. Detailed planning - Yaroslavl: Development Academy, Academy Holding, 2003. - 304 p.
SOURCES OF INFORMATION

SOURCES OF INFORMATION
1.H. Darwin http://images.francetop.net/uploads/charles%20darwin_22044.jpg 2. Hatteria http://www.infoniac.ru/upload/medialibrary/4d1/4d1bcf404cd0d2b318284ea3631c96c1.jpg 3. Snapdragon http://img0. liveinternet.ru/images/attach/c/5/87/832/87832648_9.jpg 4. Birch moth http://zagony.ru/uploads/posts/2011-08/thumbs/1313568467_015.jpg http://www. warrenphotographic.co.uk/photography/cats/11321.jpg 5. Ginkgo http://permian.files.wordpress.com/2007/02/ginkgo-tuileries.jpg 6. Polymorphism in bees http://i-pchela. ru/images/stories/family/sem.jpg 7. Ant http://www.pchelandiya.net/uploads/posts/2011-11/1322639656_x_eabc9ab21.jpg 8. Polymorphism of the dove-gray iris http://hnu.docdat.com/ pars_docs/refs/174/173704/img4.jpg 9. Seasonal polymorphism of the variable wing http://www.pesticidy.ru/ps-content/dictionary/pictures/165_content_page.jpg 10. Forms of natural selection http://ucheba-legko .ru/lections/viewlection/biologiya/11_klass/evolyutsiya/mehanizmyi_evolyutsionnogo_protsessa/lec_formyi_estestvennogo_otbora 11.Okun http://mediasubs.ru/group/uploads/se/sekretyi-ryibnoj-lovli/image2/jEyLThjZj.jpg

SOURCES OF INFORMATION
12. “Black form” of a two-spot ladybug http://www.wallpage.ru/imgbig/wallpapers_68505.jpg 13. “Red form” of a two-spot ladybug http://img10.proshkolu.ru/content/media/pic/std /4000000/3054000/3053496-c3f1628c64b89ffa.jpg

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