Summary and presentation of a lesson in biology "Struggle for existence. Natural selection and its forms" (9th grade)
Topic: Struggle for existence
Target: students’ ability to understand the complex nature of relationships in nature, the role of these relationships in the evolution of the organic world; form an idea of the struggle for existence and its forms; teach students to correctly identify forms of struggle for existence; teach students to correctly identify forms of struggle for existence and compare them with each other; develop the ability to work in a team. Equipment: task cards; diagram “Forms of the struggle for existence”, UDE Polar bear, Brown bear, answer sheets Epigraph: The offspring of a pair of flies will eat a dead horse as quickly as a lion. K. Linnaeus During the classes- Org. moment (1-2 min) Work in groups (supporters of Lamarck, Linnaeus, Charles Darwin)
IN)……………………. Talented, unlucky, fought, defended, proved, created the first evolutionary doctrine. Creator. (Jean Baptiste Lamarck)
C)………………………… Hardworking, thorough Traveled, observed, analyzed Found out the reasons for the evolution of living things Genius. (Charles Darwin)
Questions for groups: A) By what signs did you learn about the evolutionary scientists from syncwine? C) Talk about the basic principles of the evolutionary teachings of K. Linnaeus, J.B. Lamarck, C. Darwin. (one student from each group) 3. Identify and mark in the text (working with text) A) Which of the listed views and merits applies to Linnaeus? B) Which of the listed applies to Lamarck? C) Which of the listed refers to Darwin? 1. Species arose through evolution from previously living ones 2. Species were created by the creator 3. Species are unchanging, constant, eternal , there is no evolution 4. Species are fickle, slowly change, evolve 5. The diversity of species is the result of their creation by one creator according to a predetermined plan. 6. The diversity of species is the result of evolution in different conditions, the unity of species is the result of their kinship 7. The adaptability of organisms is given to them by the creator 8. Adaptability organisms are the result of evolution and internal striving9. The adaptability of organisms is the result of evolution through natural selection10. The main driving force of evolution in nature is natural selection11. The main driving force of evolution in nature is the desire of organisms for progress and self-improvement12. Organisms have heredity and variability13. The variability of organisms is the result of the influence of the external environment and the internal desire for progress.14. Organisms do not have an internal desire for progress15. Organisms have the original ability to change only expediently and usefully16. The material in the process of evolution is only hereditary variability 17. In nature, the cause of natural selection is the struggle for existence 18. For the first time developed an artificial taxonomy of organisms 19. Introduced the principle of double names 20. For the first time constructed a taxonomy of animals in ascending evolutionary order 21. Recognized “the law of inheritance of new characteristics acquired as a result of exercise or non-exercise of organs22. An idealist in his worldview.23. Scientist transformist 24. First created an evolutionary theory 25. First created a scientific theory of the evolution of the organic world, based on 3 moving forces
Slide 2
Lesson objectives:
- Form an idea of the forms of the struggle for existence.
- Form an idea of the forms of natural selection.
Slide 3
2.Natural selection
3.Tasks
1.Struggle for existence
4.Homework
Slide 4
On average, each mouse gives birth to 50 pups per year. For simplicity of calculation, we will assume that each
a mouse gives birth to 25 females and 25 males per year. Thus, the offspring of one female after 5 years is 829,425 individuals.
Explain why the number of mice on the planet is not noticeably increasing.
Slide 5
Discrepancy between the number of individuals appearing in the population and their means of subsistence
inevitably leads to a struggle for existence. The expression “struggle for existence” refers to the complex and diverse relationships of individuals within species, between species and with inorganic nature.
Slide 6
Intraspecific struggle
It arises due to the fact that individuals of the same species need similar food sources, which are also limited, similar conditions for reproduction, and similar shelters. Darwin considered intraspecific struggle to be the most intense.
Pine trees in an even-aged forest stand
Slide 8
Combating unfavorable factors of inanimate nature
It is observed in any part of the species' range in cases where external environmental conditions worsen (daily and seasonal fluctuations in temperature and humidity), as well as wherever individuals find themselves in conditions of excessive heat or cold, dryness or humidity.
Slide 9
The result of the struggle for existence is natural selection. Natural selection is a process
as a result of which, predominantly individuals with hereditary changes that are useful in the given conditions survive and leave behind offspring.
Slide 10
Stabilizing selection
Operates under constant environmental conditions. The significance of this form was pointed out by the outstanding Russian scientist I.I. Schmalhausen. Stabilizing selection is 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, the concentration of glucose in the blood in vertebrates, etc. Stabilizing selection preserves the fitness of the species by eliminating sharp deviations in the expression of the trait from the average norm, thereby protecting the existing genotype from the destructive effects of the mutation process.
Slide 11
The action of a stabilizing form of natural selection explains the stability of the size and shape of flowers in insect-pollinated plants. This is due to the fact that flowers must correspond to the structure and body size of pollinating insects. A bumblebee is not able to penetrate a too narrow corolla of a flower, and the proboscis of a butterfly will not be able to touch the too short stamens of plants with a long corolla. Thanks to stabilizing selection, relict animals have survived to this day: the lobe-finned fish coelacanth, the representative of the ancient reptiles hatteria, and the gymnosperm plant gingo.
Slide 12
Driving selection
Promotes a shift in the average value of a characteristic or property and leads to the emergence of a new average norm instead of the existing one, which no longer corresponds to the new conditions. The driving form acts when environmental conditions change.
Slide 14
Disruptive selection
It operates under conditions that favor extreme variants of a trait, but do not favor the average state. This selection is effective when, with increased competition, relatively narrow adaptations to external conditions are favorable and the population tends to be divided into smaller groups.
Slide 15
Disruptive selection
An example of discontinuous selection is the formation of different populations of the large rattle plant in connection with mowing. This form of selection occurs when plants with average flowering times are eliminated from the original population. Ultimately, a single population splits into two, located in the same territory, but turning out to be isolated from each other in terms of reproduction.
Slide 16
Speaking about natural selection in general, one must not lose sight of its creative role. Accumulating
Hereditary changes that are beneficial for the population and species and discarding harmful ones, natural selection gradually creates new, more perfect and perfectly adapted species to the environment. Natural selection is the main driving force of evolution.
Slide 17
Task 1 Determine the forms of relationships between organisms:
- In thickened kok-saghyz crops, seeds that germinate faster receive more nutrients and water. Within 20-30 days, those plants that fall under the rosettes of leaves of previously sprouted plants die.
- Cereals often suffer from bugs (yellow-green bug). Telenomus lays its egg in the turtle's egg, and the Telenomus larva eats its contents.
- After heavy snowfalls in the tundra, it is difficult for reindeer to extract moss from under the snow, and many animals die of hunger.
- Usually the prey of wolves are less fleet-footed and weaker deer.
Slide 18
Task 2
In the winter of 1898, after heavy rain and snow, researcher H.K. Bumpus collected and brought to the laboratory 136 house sparrows stunned by the elements. Of these, 72 survived and 64 died. Bumpus measured the total body length, wingspan, body weight, beak and head length, humerus length, femur length, skull width, and keel length for all individuals. His measurements showed that in surviving birds all these signs are closer to average values to a greater extent than in dead ones. The result of what form of natural selection did the scientist reveal?
Slide 19
Task 3
- Many butterfly species in non-industrialized areas have light colored bodies and wings. The development of industry, the associated pollution of tree trunks and the death of lichens living on their bark, led to a sharp increase in the frequency of occurrence of black (melanistic) butterflies. In the vicinity of some cities, black butterflies have become predominant in a short time, whereas relatively recently they were completely absent there.
- Draw up a complete diagram of the formation of a new dark-colored butterfly.
Lesson summary
(lesson using ICT). Teacher: Vorobyov D.S.
The purpose of the lesson: form the concept of the struggle for existence and natural selection as interconnected processes and as one of the central concepts of Charles Darwin’s theory of evolution; introduce the forms of struggle for existence and natural selection.
Tasks
1. Educational: To form a system of knowledge about the struggle for existence and natural selection and their role in evolution.
2. Developmental: continue work on teaching students the ability to select the main thing using various sources of information; draw up the work in the form of a diagram; publicly defend the results of creative activity;
3. educational: to form an understanding of the development of one’s intellect as a value characteristic of a modern personality;
4. didactic: create conditions for understanding new educational information and its application in educational situations, checking the level of assimilation of the system of knowledge and skills.
Lesson type: lesson in applying knowledge and skills, collective forms of work
Teaching methods: reproductive, partially search.
Form of organization of educational activities: group.
Equipment: personal computer with overhead projector; “Struggle for Existence” table, herbarium specimens of plants, insect collection, multimedia presentation
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Lesson summary
"The Struggle for Existence and Natural Selection"
(lesson using ICT).Teacher: Vorobyov D.S.
The purpose of the lesson: form the concept of the struggle for existence and natural selection as interconnected processes and as one of the central concepts of Charles Darwin’s theory of evolution; introduce the forms of struggle for existence and natural selection.
Tasks
- Educational:To form a system of knowledge about the struggle for existence and natural selection and their role in evolution.
2. Developmental: continue work on teaching students the ability to select the main thing using various sources of information; draw up the work in the form of a diagram; publicly defend the results of creative activity;
3. educational: to form an understanding of the development of one’s intellect as a value characteristic of a modern personality;
4. didactic:create conditions for understanding new educational information and its application in educational situations, checking the level of assimilation of the system of knowledge and skills.
Lesson type: lesson in applying knowledge and skills, collective forms of work
Teaching methods : reproductive, partially search.
Form of organization of educational activities: group.
Equipment : personal computer with overhead projector; “Struggle for Existence” table, herbarium specimens of plants, insect collection, multimedia presentation
Teacher activities | Student activities |
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I. Testing knowledge. 1.Testing. 1) The elementary unit of evolution is: a) population; b) individual; c) type; d) biocenosis. Answer: a). 2) Elementary evolutionary material is supplied by: a) mutations; b) modifications; c) population waves; d) selection. Answer: a). a) natural selection; b) isolation; c) migration; d) mutations. Answer: a). 4) Genetic drift is: a) increase in the number of individuals; 6) random changes in the concentration of genes in the population; c) migration of individuals from population to population; d) free crossing between individuals in a population. Answer: b). 6) Genetic balance in a population is: a) constancy of the number of all individuals in the population; b) constancy of frequencies of occurrence of various alleles; c) equal number of females and males; d) the balance of fertility and mortality in the population. Answer: b). 7) Sharp fluctuations in population numbers: a) do not affect the frequency of alleles in the gene pool of the population; b) change the gene pool of the population; c) always lead to the loss of dominant alleles; d) usually associated with the loss of recessive alleles. Answer: b). 2. Written response on the card. Exercise. Indicate the numbers of the sentences in which errors were made and correct them. 1. In different populations of the same species, the frequency of mutant genes is the same(not the same). 2..
Both closely located and distant populations of the same species do not differ from each other(may differ significantly from each other). 4. This is explained by the fact that in populations of one species only directed changes in the gene pool occur(not only directed, but also undirected, random changes in gene frequency). 5. When animals and plants migrate, the gene pool of the newly formed population is much larger(less) gene pool of the parent population. 3. Written answer at the board. Exercise. Make a diagram “Causes that disrupt genetic balance in populations.” | Differentiated task Level A – 1 task Level B – task 2 Level C – task 3 (individual, differentiated work) |
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II. Learning new material
(Slide 4) | Work in 3 groups by sections(CSR) Intraspecific struggle Interspecies fight Fighting adverse conditions Annex 1, paragraph 57c 206-207 Search for information 1.disc “General Biology Grade 11” Cyril and Methodius 2. “Ecology 10-11” |
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III. Consolidation and application of knowledge. Systematization of knowledge acquired by students. Appendix 2. Slides 5-11 | Group reports on the work done. Filling out the table - Appendix 2 |
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IV. Learning new material 1. Completing tasks in groups. 1st group gets acquainted with the text on p. 233-236 of the textbook and determines the signs of driving selection. 2nd group gets acquainted with the text on p. 236-237 of the textbook and determines the signs of stabilizing selection. 3rd group works with additional literature material(see list of literature for the lesson)and identifies signs of disruptive selection (slides 12-17) | Collective creative work taking into account students’ abilities |
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V.Secure the material Fill in and explain
| protect your part of the circuit - |
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VI. Reflection on learning the material. 1. Listed are the reasons that lead to the death of many dandelion individuals and prevent this species from occupying the entire globe: a) the fruits, along with the hay, enter the sheep’s stomach; b) many birds eat fruits; c) herbivores feed on seedlings; d) trampled by people, cars, tractors; d.) other taller plants interfere; f) dandelions crowd out each other; g) seeds die in deserts, on rocks; H.) seeds die in the middle zone if they fall i) plants die from severe frosts and drought; j) plants die from pathogenic plants and viruses. Indicate the forms of struggle for the existence of dandelions (intraspecific: ...; interspecific: ...; struggle against unfavorable environmental conditions: ...). 2. Determination of the forms of natural selection. Determine what form of natural selection these examples can be attributed to:
| Working with the dough. Checking the results. |
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VII. Homework:paragraph 57, 58 questions p. 207 No. 1-3 - reproductive level. Advanced level-Based on your own observations, prepare examples that describe the struggle for existence between organisms: a) of the same species; b) different types. | Students write homework according to their abilities. |
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VIII. Assessing and summarizing the lesson. Have you achieved your goals and objectives? What difficulties did you encounter? Self-esteem. Appendix 3 | self-esteem |
Annex 1
Charles Darwin first came to the idea that the driving force of the entire evolutionary process is the result of the interaction of organisms with each other and with the external environment.
Charles Darwin drew attention to the fact that all living organisms have the ability of almost “limitless” reproduction. As an illustration, he looked at the example of the reproduction of an elephant, one of the slowest reproducing animals. Even in this case, from one pair of elephants, at the usual rate of reproduction, about 19 million animals should appear in 740-750 years.
In the vast majority of cases, the rate of reproduction of organisms is much higher. For example, the offspring that one daphnia is potentially capable of producing over the summer reaches an astronomical size - more than 10 million individuals, which exceeds the mass of the Earth.
At the same time, unlimited growth in the number of organisms in nature is not observed. What is the reason for this phenomenon? Most individuals die at different stages of development and leave no descendants behind. It is known that the higher the reproduction rate of individuals of a given species, the more intense the death rate.
Beluga lays about a million eggs during spawning, and only a small part of them goes through the full development cycle and reaches adulthood. The same applies to
plants.
According to Darwin, the discrepancy between the possibility of unlimited reproduction of species and limited resources is the main reason for the struggle for existence. The death of descendants occurs for various reasons. Sometimes it can be random (forest fire, flood, intervention
person).
However, as a rule, death is selective. One should not think that an organism with unfavorable signs must necessarily be left without offspring or die. There is simply a high probability that this particular organism will leave fewer descendants or die. Consequently, organisms that have a set of properties that give them the greatest adaptability to living conditions are more likely to survive and reproduce more efficiently.
2. Forms of the struggle for existence.
Darwin distinguished three forms of struggle for existence: intraspecific, interspecific, and struggle against unfavorable conditions of inorganic nature.
Charles Darwin pointed out that the struggle for life is especially persistent between organisms within the same species, and substantiated his statement by the fact that they have similar characteristics and experience the same needs. A striking example of intraspecific struggle is competition between trees of the same age in a coniferous forest. The tallest trees, with their widely spread crowns, intercept the bulk of the sun's rays, and their powerful root system absorbs dissolved nutrients from the soil to the detriment of weaker neighbors. Intraspecific competition intensifies with increasing population density. When there is an abundance of chicks in some bird species (many species of gulls, petrels), the stronger ones push the weaker ones out of the nest, dooming them to death from predators or starvation.
Interspecific struggle should be understood as competition between individuals of different species. Interspecific struggle reaches particular severity in cases where species that live in similar ecological conditions and use the same food sources compete.
As a result of interspecific competition, either the displacement of one of the opposing species occurs, or the adaptation of species to different conditions within the same area, or their territorial separation. For example, gray and black rats are different species of the same genus. In human settlements in Europe, the gray rat has completely replaced the black rat, which is now found in forested areas and deserts. The gray rat is larger, swims better and, most importantly, is more aggressive, as a result of which it has the upper hand in fights with the black one.
In the forest, under the protection of light-loving species - pine, birch, aspen - at first spruce seedlings develop well, which freeze in open areas, but then, as the crowns of young spruce trees close, the seedlings of light-loving species die.
Interspecific struggle for existence involves the unilateral use of one species by another, the so-called “predator-prey” relationship (fish eating plankton).
Examples of the struggle for existence are not limited to struggle in the literal sense. Thus, a form of struggle for existence is the favoring of one species by another without harming itself (birds and mammals distribute fruits and seeds), the mutual favoring of different species to each other (flowers and their pollinators).
In the forest, the benefits of plants growing together are also observed. Here, compared to open places, a different thermal, water and air regime is created: less sharp temperature fluctuations, higher relative humidity - shade-tolerant shrubs, grasses, mosses, and ground algae grow under the canopy of trees in the upper tiers.
The third form of struggle for existence is the struggle against unfavorable external conditions. Factors of inanimate nature have a direct impact on the evolution of living things. Plants in the desert are said to “fight drought,” meaning the development of numerous adaptations that help them obtain water and nutrients from the soil (special root system) or reduce the rate of transpiration (special leaf structure).
The conditions of the inorganic world not only have a significant impact on the evolution of organisms in themselves, but their influence can strengthen or weaken internally and interspecific relationships. With a lack of territory, heat or light, intraspecific struggle intensifies and, conversely, with an excess of resources necessary for life, it weakens.
Appendix 2
Comparative characteristics of forms of struggle for existence
Forms of struggle for existence | Definition | Examples | Causes | Implications for evolution |
Signs | Driving selection | Stabilizing selection | Disruptive selection |
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C. Darwin | I.I. Schmalhausen | |||
Terms of action | Gradual and unsharp change in the living conditions of organisms | In unchanging constant conditions of existence | Under sharply changing conditions of existence |
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Focus | Schemes of action of forms of natural selection Eliminated forms on population curves (elimination) | |||
In favor of individuals with deviations from the average norm | against individuals with short deviations from the average norm | against individuals with average trait values |
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Result of action | the emergence of a new average norm of a trait | preservation and maintenance of the value of the average norm of the trait | formation of new average norms instead of one |
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Examples | Industrial mechanism; Sustainability to pesticides; -microorganisms and antibiotics | Down syndrome; Sustainable Relic | Polymorphism; Early flowering Fast growing |
Literature:
1. Kamensky A.A. General biology: textbook for grades 10-11. Bustard 2009
2. Vysotskaya, L. V. General biology: a textbook for grades 10-11 with in-depth study of biology / L. V. Vysotskaya, S. M. Glagolev, A. O. Ruvinsky and others - M: Education, 2001. - P. 265-266.
3. Green, N. Biology: in 3 volumes / N. Green, W. Stout, D. Taylor; edited by R. Soper. - M: Mir, 1990. - P. 290.
4. Sivoglazov, V. I. General biology. A basic level of. 10-11 grades / V. I. Sivoglazov, I. B. Agafonova, E. T. Zakharova. -M.: Bustard, 2005.
Theme: Struggle for existence
For the teacher -Goal : students’ ability to understand the complex nature of relationships in nature, the role of these relationships in the evolution of the organic world; form an idea of the struggle for existence and its forms; teach students to correctly identify forms of struggle for existence; compare them with each other; develop the ability to work in a team.
For student - Goal: to know the definitions of the struggle for existence, the role of struggle in the evolutionary process
Be able to: give examples of all types of struggle for existence in animals and plants.
Develop the ability to work with text, generalize, and draw conclusions.
Equipment: task cards; visualization - pictures of animals: Polar bear, Brown bear, camel, jerboa, plants - cactus, aloe. presentation.
Epigraph : The offspring of a pair of flies will eat a dead horse as quickly as a lion.
K. Linnaeus
Lesson form - learning new knowledge - innovative
1 introductory explanatory part
1.Introduction to the structure of the lesson, goals and objectives of the lesson
Part 2 Educational and developmental part - a brief explanation using concepts and diagrams. Active form of cognition..
3. Consolidative – correctional As a continuation of development, updating of knowledge,
4. Control evaluation - monitoring of children's learning - test
Organizing time. Greetings. Communicating tasks and work stages. Motivation and attitude towards fruitful activity
During the classes
Hello guys.
Guys, what is evolution - (an irreversible process of historical development of living organisms)
Who answered the question why evolution occurs - (Ch Darwin)
What are the three main causes of evolution, the driving forces, named by Darwin.
Struggle for existencepresentation on the topic: "The struggle for existence."
Logistics: interactive board
Seating at a round table.
During the classes
Lesson steps
Teacher's activities
Student activities
1. Org. moment.
(1 min.)
1Introductory and explanatory part (introduction to the structure and objectives of the lesson)
Preparation for learning
slide
2 .Educational and developmental part. (brief explanation of the topic
using diagrams... Concepts,.active form).Learning new material.
Choose the correct definition
TYPES OF WRESTLING
Slide 9
teacher
Group work
Working with textbook text
valeopause
notebook
consolidation
Reflection
assessment
D/Z
Teacher 2 stars 1 wish
Hello
Epigraph of the lesson - WHY don’t all living organisms live together.
And you are a friendly class
Guys, what is it?
evolution? –(irreversible process of historical development of living organisms
Who answered the question why evolution occurs.
Name the driving forces of evolution
We begin to study the topic:The struggle for existence §40 p.191
ZHU-slide-appoint someone responsible (Dasha)
(can you give an example of competition between animals and plants. Why does this happen?
Staging1. Problematic question_ slide
Who is the winner in this fight?
What “prize” does he get?
2 Causes of the struggle for existence
Unlimited ability of living organisms to reproduce (excessive numbers) by students.
-(discrepancy between the possibility of species for unlimited reproduction and limited resources) Darwin believed that excess numbers lead to a struggle for existence
What do you think is the reason for this phenomenon?
Most individuals die at different stages of development and leave no descendants behind.
Sample answer: What are the reasons?
Reasons: - it is natural - climatic factor; fight with individuals of other species; - between individuals of their own species. It is known that the more intense the death of organisms is, the higher the reproduction rate of individuals of a given species.
definition
The struggle for existence A complex of relationships between living organisms, including competition, symbiotic relationships
A complex of relationships between living organisms and the environment, including mutual assistance, competition, symbiotic relationships
While they are thinking, SASHA and I are working on a basic scheme - definitions and types.
Darwin identified three forms of struggle for existence: (Slide No. 9)
1.- intraspecific, 2. - interspecific, 3. - combating unfavorable environmental conditions.
Let us consider each form of struggle for existence.
Intraspecific struggle for existence. ( p.191) read, find reasons, directions, give an example.
Definition - Volodya
Dasha is an example, Olya -
conclusion - Sasha.
Natasha -support diagram I work at the board
Reasons (for food, for territory, for sexual selection
Conclusion: (Occurs between individuals of the same population of any species. This is the toughest and most acute, since all individuals of the same species need the same and, moreover, limited resources: food, living space, shelters, breeding sites.
Examples : - - sometimes tits trample 1-2 chicks into the nest litter.Dasha
Olya - rivalry over territory;Examples: - brown bear marks boundaries
your plot with scratches on the wood;
Wolf marks territory with urine
-Sasha - male tits and finch announce the occupation of a site with a song..
Conclusion: although intraspecific the struggle for existence is accompanied by a decrease in fertility and the death of some individuals of the species, it nevertheless determines the prosperity of the species as a whole and contributes to its improvement.
Interspecific struggle for existence is a struggle between individuals of different species.
Make pairs of relationships from the chain: wolf, pine. Hare. Clover. Dodder. Birch, tapeworm. cow
THROWING PAPER “crumpled paper” (moving)
The SOUND of singing activates the brain. “WE WE, WE, WE
Read and draw conclusions
Conclusion: the form of this struggle leads to the evolution of both interacting species to the development of mutual adaptations. It also strengthens and aggravates intraspecific struggle.
ABIOTIC FACTORS
Fighting adverse conditions Olya – MESSAGE-anticipatory task
-adaptation to seasonal phenomena
Natural disasters. Adaptation
environment. ( Slide No. 24) WORK WITH HERBARIUM, CACTUS, DRAWINGS POLAR BEAR, CAMEL
Conclusion: the winners are the most viable individuals (with efficient metabolism and physiological processes).
Help - page 192 of the textbook.
There is a struggle -Indirect, and direct answer complete the tasks in the workbook 129 “65
They call it by slide
1.The type of wrestling is called out loud in a chain
Fighting leads to population control and natural selection
2. Slide with the task - self-control
I FOUND OUT
Assigned before the lesson Dasha 2 stars stars and 1 wish
Paragraph No. 40
R-role optional
A-audience
F-letter
T-Struggle for existence
0 animals were awarded medals in WWII - carrier pigeons, dogs, cats, mullahs 60 thousand - dogs, of which 16 thousand sled dogs saved 700 thousand wounded, 6 thousand mine detectors
Wish At the beginning of the lesson I asked if your class is friendly - be friendly, end the lesson with a song about friendship
Answer questions
Write down and name the objectives of the lesson
Perception and partial understanding of the newThey write it down.
Listens to students Answer questions with justification for their answer. (Why do you think so? Participate in dialogue with the teacher Offer your answers with justification, make the necessary notes. Vocabulary work
Competition relationships between species with similar ecological requirements
Help (the wolf leaves a trail of food for the others)Example: - this is the upbringing and protection of offspring, joint feeding of cubs (in a family of bees, a herd of horses).
Symbiosis - mutually beneficial relationship)
Repetition, repeated recitation, scheme
The topic of the lesson is “The struggle for existence.”
Lesson objectives:
- study the essence of the struggle for existence; show the significance of Charles Darwin's theory for modern science; strengthen understanding of the relationships between organisms and the environment.
- personality-oriented motivation of students, highlighting the main thing, developing the ability to analyze
- nurturing cognitive interest in the material being studied, environmental education, and a sense of civic responsibility.
Lesson type: learning new material.
Equipment:
During the classes
Organizing time
-Communication of the topic and objectives of the lesson
- Psychological attitude
2.Learning new material.
Lesson problem.
Mighty nature is full, full of miracles. (A.S. Pushkin)
What natural wonders are they talking about?
Students offer different versions. We will answer the lesson question by studying the topic of the lesson.
One of the conditions of natural selection in nature, Darwin considered the possible overpopulation of species, arising as a consequence of the geometric progression of reproduction. For example, an roundworm produces up to 200 thousand eggs per day, a female cod spawns up to 10 million eggs, one sow thistle plant produces up to 19 thousand. seeds, and henbane - more than 400 thousand. And so, the fertility of organisms in general is very high, but not all survive to reach sexual maturity. A significant part of the offspring die for various reasons. Darwin concludes that between organisms there arises struggle for existence.The struggle for existence is complex and diverse intraspecific and interspecific relationships, as well as the relationships of organisms with environmental factors.
Independent work of students
Assignment: Fill out the table “Forms of the struggle for existence” using the text of paragraph 41, pp. 186-188
Fight form
Definition
Causes
Result of the struggle
Intraspecific
Interspecific
Fighting adverse conditions
A list of competing organisms and abiotic factors is given. Use the “+” sign to indicate the type of struggle for existence
Examples of competing organisms
Intraspecific struggle
Interspecies fight
With abiotic factors
straight
indirect
Between closely related species
Predator\
victim
1.Hare/wolf
2.Wolf\wolf for female
3.Hare\rabbit
4.Wolf\fox
5. Birch\birch
6.Wolf\deer
7.Birch/pine
8.hare/flood (flood)
9. Fox\deep snow
10. Birch \forest fire
3. Consolidation of the assimilation of the material.
test
Which process is one of the driving forces of evolution?
A) struggle for existence;
B) Relative fitness of organisms;
C) Heredity;
D) variability.
2. How is the interspecies struggle for existence expressed?
A) Competition between individuals of different species;
B) Competition between individuals of the same species;
C) Reaction to unfavorable conditions of inorganic nature;
D) Limiting the habitat area with a system of marks.
3. In its habitat, the black rat is replaced by the gray rat, spruce develops well under the protection of deciduous forest, and then shades it. What form of struggle for existence do such examples reflect?
A) Intraspecific;
B) Interspecific;
B) Symbiosis;
D) Combating abiotic environmental factors
4. There is a lonely birch tree at the edge of the forest. Is there a struggle for existence in this case?
A) yes, intraspecific;
B) yes, interspecific;
C) combating unfavorable conditions;
D) there is no struggle.
4. Listed are the reasons that lead to the death of many dandelion individuals and prevent this species from occupying the entire globe:
a) the fruits, along with the hay, enter the sheep’s stomach;
b) many birds eat fruits;
c) herbivores feed on seedlings;
d) trampled by people, cars, tractors;
d.) other taller plants interfere;
f) dandelions crowd out each other;
g) seeds die in deserts, on rocks;
H.) seeds die in the middle zone if they fallin conditions unfavorable for preservation and germination;
i) plants die from severe frosts and drought;
j) plants die from pathogenic plants and viruses.
Indicate the forms of struggle for the existence of dandelions (intraspecific: ...; interspecific: ...; struggle against unfavorable environmental conditions: ...).
A competition to see who can quickly give more correct examples of different types of struggle for existence in plants and animals.
Question: Which form of struggle for existence is the most acute? Why?
4. Lesson summary: We answer the problem of the lesson: as a result of the struggle for existence, natural selection occurs, organisms adapted to the environment give a miracle of nature - diversity of species! Have we answered the lesson question? Charles Darwin deduced the basic laws of nature.
Lesson grades.
5. Homework: paragraph 41 pp. 186-188