Abstract on the topic “The driving forces of evolution. The struggle for existence and natural selection"
Plan
Struggle for existence.
Forms of the struggle for existence
Natural selection is the leading driving force of evolution.
Forms of natural selection.
The creative role of natural selection.
Sexual selection.
Struggle for existence.
The struggle for existence is one of the factors of evolution and one of the basic concepts in the theory of evolution of Charles Darwin.
Struggle for existence - the whole set of relationships between individuals and various environmental factors. These relationships determine the success or failure of a given individual in the struggle for existence.
According to Darwin, the struggle for existence is the result, on the one hand, of a tendency towards limitless reproduction, and on the other, of limited natural resources, that is, the discrepancy between the intensity of reproduction and the means of life leads to the struggle for existence.
Here are examples of high fertility of species:
The cholera bacillus can produce offspring weighing 100 tons per day;
The offspring of a pair of sparrow-sized birds with a lifespan of 4 years can cover the entire globe in 35 years;
The offspring of one dandelion in 10 years can cover a space 15 times larger than the landmass of the globe (example by K. A. Timiryazev);
The offspring of a pair of flies will eat a dead horse as quickly as a lion (example of C. Linnaeus), etc.
The higher the probability of extermination of offspring, the higher the fertility of a species.
The breeding potential is high, but the number of adult individuals of the species is constant. Why? Because most of the individuals die before reaching the age of sexual maturity in the struggle for a means of subsistence.
What does the expression mean: “An individual has achieved success in the struggle for existence?” The highest reward in this competition is leaving offspring, passing on genes to subsequent generations, and not just preserving life. Failure in the fight does not always mean the death of a given individual, but more often, non-participation in reproduction. The consequence of the struggle for existence is natural selection.
Charles Darwin identified three forms of struggle for existence: intraspecific, interspecific, and struggle with unfavorable environmental conditions.
Forms of the struggle for existence
Intraspecific – 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.
Conclusion: the form of this struggle determines the prosperity of the species as a whole and contributes to its improvement.
Example: Dandelion population.
Interspecific – It is acute if the species belong to the same genus and require the same conditions of existence.
Example: The gray rat, larger and more aggressive, has replaced the black rat in human settlements.
Interspecies struggle includes relationships like:
predator →prey
plant →herbivore
Conclusion: the form of this struggle leads to the evolution of both interacting species, to the development of mutual adaptations in them. It also strengthens and aggravates intraspecific struggle.
Combating adverse environmental conditions also enhances intraspecific competition, since individuals of the same species compete for food, light, warmth, etc.
Conclusion: The winners are the most adapted individuals (with efficient metabolism and physiological processes). If biological characteristics are inherited, then the species' adaptations to the environment will improve.
N.B.! Task No. 1
Characteristics of forms of struggle for existence.
| Fight form | Result of the struggle | Examples from the animal kingdom | Examples from the plant kingdom |
| Intraspecific | |||
| Interspecific | |||
| With environmental conditions |
Natural selection is the leading driving force of evolution.
The factors of the evolutionary process we have considered are non-directional, largely random in nature. The only directional factor is natural selection. It is a consequence of various types of relationships of living beings with each other and with environmental conditions, that is, a consequence of the struggle for existence. What is natural selection?
Natural selection - a process as a result of which the most adapted individuals of each species predominantly survive and leave offspring and the less adapted ones die.
Selection characteristics:
A necessary prerequisite is hereditary variability;
Character is directional, it is always directed towards greater adaptability to environmental conditions;
The selection factor is the natural environment with its own conditions;
Genetic essence - consists in the non-random preservation of certain genotypes in a population and their selective participation in the transmission of genes to the next generation;
The result is a transformation of the population's gene pool, the formation of adaptations;
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.
Darwin's concept of natural selection was further developed in the works of S. S. Chetverikov, I. I. Shmalhausen, R. Fischer, S. Wright, F. G. Dobzhansky and others.
Natural selection is revealed quite fully only in fairly large populations, since as the population decreases, the role of random factors increases.
Forms of natural selection.
Natural selection in nature acts in different directions and accordingly leads to different results. Therefore, it is customary to distinguish several forms of natural selection. Let us give their characteristics.
Driving (directed, leading) selection - 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). As a result of driving selection, mutations accumulate and spread in the gene pool of the 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.
Let us give examples of the action of driving selection. For example, an increase in the body size of a horse (remember the phylogenetic series of the horse), a decrease in the body size of elephants on the islands of the Mediterranean Sea, industrial melanism (darkening of the body covers of animals in industrial centers), the development of resistance to pesticides in insects, etc.
Stabilizing selection - observed when constant environmental conditions are maintained for a long time.
Stabilizing selection favors the preservation in the population of the optimal phenotype under given conditions, which becomes predominant and acts against the manifestation of phenotypic variability. In this case, the population remains phenotypically homogeneous, but its gene pool can change based on the appearance of mutations with the same average value, but with a narrower reaction rate. Examples of stabilizing selection are the preservation of the size and shape of a flower 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.). Thus, stabilizing selection guards the constancy of species, ensuring their phenotypic invariability.
Disruptive (from lat.disruptus - torn),tearing selection - 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. When discontinuous selection acts within a population, polymorphism usually arises - several clearly 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. Sometimes disruptive selection is considered as a special case of driving selection, since it, unlike stabilizing selection, leads to a change in the phenotypic appearance of the population.
Driving and stabilizing selection operates in medium-sized populations, while disruptive selection operates in large populations or areas. Driving and stabilizing selection are closely related to each other and often replace each other.
For example, on oceanic islands, flies with normal wings are blown into the ocean and die. The advantage is found in long-winged animals that resist the wind, and in organisms with underdeveloped (rudimentary) wings that switch to a crawling lifestyle.
The creative role of natural selection.
Critics of Darwinism attributed to selection the role of a “sieve” or “gravedigger”, eliminating or sorting out changes in populations. Such a result of selection actually exists in nature. But selection not only (!) eliminates the less fit, but also determines:
direction of evolution;
pace of evolution.
The same material, supplied by mutations, waves of life and other factors of evolution, depending on the direction of selection, can lead to different results. Acting for an unlimited period of time (millions and billions of years), natural selection, together with other evolutionary factors, genetic drift and isolation, created a huge variety of species in living nature, adapted to life. This reveals the creative role of natural selection.
Circumstances favoring natural selection:
High incidence of unspecified hereditary changes
Numerous individuals of a species, increasing the likelihood of beneficial changes
Unrelated crossing, increasing the range of variability in the offspring
Isolation of a group of individuals, preventing them from interbreeding with the rest of the organisms of a given population
Wide distribution of the species.
6. Sexual selection.
Sexual selection- a form of natural selection in some animal species, based on 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 horns, etc.). These signs can be harmful to both 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?
N.B.! Task No. 2 Using the textbook and other information resources, fill out the table in your workbook.
Comparison of artificial and natural selection
| Indicators | Artificial selection | Natural selection |
| Source material for selection | ||
| The path of favorable changes | ||
| The Path of Unfavorable Change | ||
| Nature of action | ||
| Selection result | ||
| Selection forms |
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
Download:
Preview:
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 |
||||||||||||||||||||||||
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) |
||||||||||||||||||||||||
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” |
||||||||||||||||||||||||
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 |
||||||||||||||||||||||||
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 |
||||||||||||||||||||||||
V.Secure the material Fill in and explain
| protect your part of the circuit - |
||||||||||||||||||||||||
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. |
||||||||||||||||||||||||
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. |
||||||||||||||||||||||||
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 |
|
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 |
|
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 |
||
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 |
|
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 newRecording.
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
City Department of Education
Open biology lesson
at a city seminar
Deputy Directors for HR
"Struggle for existence
and natural selection"
Grade 11
Egorova Elena Yurievna
Uralsk, 2015
Short-term plan for an open lesson in biology in grade 11 “B”
teacher: Egorova E.Yu.
Secondary school No. 32, Uralsk, West Kazakhstan region
| date | Lesson 23 | Grade 11 | ||||||||||
| Title of the lesson: | The struggle for existence and natural selection. | |||||||||||
| Common goal: | Continue studying the driving forces of evolution using the example of the struggle for existence and natural selection, introduce the forms of the struggle for existence and natural selection. Develop the ability to compare, analyze, draw conclusions, develop imaginative thinking, and public speaking skills. | |||||||||||
| Learning outcomes | Learn the connection between the factors of natural selection and the driving forces of evolution. Learn to compare biological processes. Justify the conclusion about the factors of evolution. | |||||||||||
| Key Ideas | There are three forms of struggle for existence: intraspecific, interspecific and struggle against unfavorable conditions of inorganic nature. The struggle for life is especially persistent between organisms within the same species, because they have similar characteristics and experience the same needs. | |||||||||||
| Class | Reflection(10 minutes) - (When entering the classroom, students choose stickers of different colors and sit in rows of different colors) Let's restore in our memory the knowledge about evolution, its driving forces and evolutionary scientists. A) computer testing – green stickers (I row) B) test – survey – yellow stickers (II row) B) biological ping - pong (front poll) – pink stickers (III row) Summative assessment Peer assessment | Updating knowledge about the struggle for existence and natural selection (after listening to the poems, students must determine the topic of the lesson and its purpose) Poems: /WITH. Yesenin/ And there's a snowstorm in the yard Lays a silk carpet, But it's painfully cold. Sparrows are playful, like lonely children Huddled by the window. The small birds are cold, hungry, tired, And they huddle tighter... (combat unfavorable conditions) / P. Usachev/ Forest all around, wide clearing... On the wide grass near the mound Black grouse are engaged in a hot battle... (intraspecific struggle) /A. Markov/ Do you know, friends, that the hedgehog Have you ever had soft fur? But suddenly a fox appeared The wolves clicked their teeth - And the eyes became prickly, and needles grew. (interspecific struggle) /A. Osmolov/ Do not harm the starling. Protecting the human race, Our ever-present assistant, He fights with the formidable locusts - The enemy of collective farm arable land... (interspecific struggle) Formative assessment | ||||||||||
| Lesson epigraph: “Life is a struggle” As you know, all organisms leave offspring, sometimes very numerous. One herring individual lays on average about 40 thousand eggs, sturgeon - 2 million, frogs - up to 10 thousand eggs, gray rat - 5 litters per year. On one poppy plant, up to 30-40 thousand seeds ripen annually. Even slowly reproducing animals have the potential to leave a huge number of offspring. Female elephants give birth to calves between 30 and 90 years of age. Over 60 years, they give birth to an average of 6 elephant calves. Calculations show that even with such a low reproduction rate, after 750 years the offspring of one pair of elephants would amount to 19 million individuals. Based on these and other examples, Darwin comes to the conclusion that in nature, any species of animals and plants strives to reproduce. At the same time, the number of adults of each species remains relatively constant. Each pair of organisms produces many more offspring than survive to adulthood. Most of the organisms that are born die. What is the cause of death?(discussion by students) – presentation. In life, there is constantly a struggle between living organisms at different levels. That's why the purpose of our lesson: study the essence of the struggle for existence as the main factor of evolution, get acquainted with the main forms of the struggle for existence. The causes of death are varied: Lack of food due to competition between individuals of the same species Enemy attack The effect of unfavorable environmental factors (drought, severe frosts, high temperatures, etc.) This leads to a new conclusion made by Darwin: In nature there is a continuous struggle for existence. Darwin himself wrote: “... I must warn that I use this term in a broad sense, including here the dependence of one creature on another, and also including not only the life of one individual, but also its success in leaving behind offspring. For the sake of convenience, I resort to the general term"struggle for existence." In other words, struggle for existence is a set of complex relationships that exist between organisms and environmental conditions. | On your desks there are pictures of various forms of struggle for existence, identify these forms, identify the main reasons for various types of struggle for existence, their meaning - associations from pictures, filling out a flipchart. Complete the association as you watch the video “Struggle for Existence.” Formative assessment. Reading marked “INSERT”- Intraspecific struggle (§13 p.82) The toughest and sharpest, because... all individuals of the same species need the same resources: food, territory, shelters, breeding sites. N/r, birds of the same species compete for nesting sites. During the breeding season, males of many species of mammals and birds compete with each other for the opportunity to start a family. Interspecies fight (§13 p.84) Includes relationships like: predator - prey (wolves, foxes hunt hares, between wolves and hares, between foxes and hares there is an intense struggle for existence); There is also competition for food between predators (wolves and foxes). The existence of grasses depends not only on their consumption by animals, but also on other conditions: pollination, competition for light, moisture. (§13 p.85) Factors of inanimate nature have a huge impact on the survival of organisms. Many plants die during cold winters with little snow. In severe frosts, mortality also increases among animals living in the soil. In winter, when there is a lack of oxygen dissolved in the water, fish die. Plant seeds are often brought into unfavorable habitats and do not germinate. CONCLUSION: |
|||||||||||
| 6. appendix to the lesson “Forms of natural selection” - filling out a conceptual table. Formative assessment In the struggle for existence, those individuals that survive and leave offspring are those that have such a complex of characteristics and properties that allow them to compete most successfully with others. natural selection . Knowing that there are three types of struggle for existence, can we assume the existence of different forms of natural selection? Answer: yes, you can. What causes these different forms? Answer: environmental conditions. “Pivot table” - EO forms
|
||||||||||||
| Reflection –“California Sandwich”, lesson summary (write “+” and “-” of the lesson on stickers) and attach them to emoticons based on your mood during the lesson. Current assessment |
||||||||||||
| Sources, facilities and equipment | Multimedia installation, presentation, posters, markers, notebooks, textbooks “Biology” 11th grade Kovshar A.F., Solovyova A.R., Kayym K. et al. | |||||||||||
| Follow-up task | Internet - resources, notes and diagrams in notebooks, §13-15. | |||||||||||
Lesson route sheet
Greeting, division into rows (using stickers): (1 minute)
Checking homework: (8–9 minutes)
A) Tests (on paper or computer testing) :
1. A long continuous and irreversible historical process?
A) aromorphosis B) idioadaptation
C) evolution D) degeneration
Complication and improvement of living organisms?
A) biological evolution B) idioadaptation C) evolution D) degeneration
Founder of taxonomy?
D) J. Ray
Binary nomenclature was proposed:
The criterion that K. Linnaeus used in his taxonomy:
A) genetic B) morphological
C) physiological D) geographical
How many criteria are there of the type...
A) 4; AT 6; C) 8; D) 10;
Scientist evolutionist who formulated the first evolutionary theory at the beginning of the 19th century:
A) C. Darwin B) J. B. Lamarck C) C. Linnaeus
Explained the principle of gradation of living organisms:
A) C. Darwin B) J. B. Lamarck C) C. Linnaeus
A) C. Darwin B) J. B. Lamarck C) C. Linnaeus
Charles Darwin identified the driving forces of evolution as: A) the struggle for existence;
B) hereditary variability; C) natural selection; D) all answers are correct
Evaluation criterion: 0-1 error - "5"; 2-3 errors – "4"; 4-5 errors – "3"; more than 5 errors – "2".
B) Biological ping-pong (frontal survey)
What is evolution? (this is a long continuous and irreversible historical process of development of the organic world)
What do you understand by biological evolution? (irreversible process of gradual complication and improvement of living organisms on the path of their adaptability to environmental conditions)
The founder of taxonomy, who did not assume an evolutionary process in living nature? (C. Linnaeus)
What does binary nomenclature mean? Who suggested it? (C. Linnaeus compiled the best taxonomy of his time, simplified the existing terminology and proposed binary nomenclature - a double species name: adjective - species, noun - genus)
What criterion was first developed by C. Linnaeus to create taxonomy? (morphological, since for division and systematization he was guided by external features)
How many criteria are there in total? List them? (six: morphological, genetic, physiological, biochemical, environmental, geographical)
Why is it currently not the morphological, but the genetic criterion that is considered the main one when determining the species? (it is considered more reliable, because the ability to interbreed and produce fertile offspring can only be found in individuals in a population with the same number, structure, size and shape of chromosomes. There are species of twins that are absolutely morphologically identical, but genetically differ in the number or structures of chromosomes)
A scientist evolutionist, transformist, who formulated the first evolutionary theory at the beginning of the 19th century? (J.B. Lamarck)
What did J.B. base his classification of animals on? Lamarck? And what did you notice? (the structure of the nervous and circulatory systems, I noticed that animals seem to be on the steps of a ladder, becoming more complex from simple ones - that is, gradation occurs, which means that the world of living nature is changing, it is improving).
Who was the first evolutionary scientist to draw attention to the fact that the environment influences changes in living organisms? (J.B. Lamarck)
Why did J.B. Lamarck fail to reveal the causes of evolution? (he made a number of mistakes, believing, firstly, that every living organism strives for perfection, and, secondly, that in the course of exercise or non-exercise of organs, organisms achieve perfection and pass on these characteristics by inheritance)
How did Charles Darwin's trip around the world influence his works? (the diversity of plants and animals, the remains of extinct living organisms, his observations, collections, drawing up geographical maps - all this allowed him to come to the conclusion about the variability of species in nature, and as a consequence, the evolution of species)
Charles Darwin's main merit is not in the formation of the evolutionary theory itself, but in the fact that he revealed the causes of evolution. What are they? (causes or driving forces of evolution).
What are the driving forces of evolution? (struggle for existence, natural selection and hereditary variability)
Listen to the poems and try to determine the topic of our lesson and its purpose.
(2 minutes)
On your desks there are pictures of various forms of struggle for existence, identify these forms, find the formulation of the forms of struggle for existence, identify the main reasons for various types of struggle for existence, their meaningfor organisms. (5-7 minutes)
Intraspecific struggle(§13 p.82)
Interspecies fight(§13 p.84)
Combating adverse environmental conditions(§13 p.85)
Discussion - defense of work in a group(7-10 minutes)
Watching a video fragment and discussing it(3 minutes)
CONCLUSION: All forms of struggle for existence are accompanied by the death of a huge number of organisms or lead to the fact that some of them do not leave offspring.
In nature, there are processes of selective destruction of some individuals and preferential survival of others- this phenomenon was called by Charles Darwin natural selection . What forms of natural selection do you know? §15 + (look on the back of the sheet)
(8 minutes)
Consolidation - task on slides about the struggle for existence. (3 minutes)
Reflection(1 minute)
Lesson summary andD/z § 13.15(1 minute)
Student score sheet
| F.I. studying | Checking homework (grade, points) | Work on a new topic | Lesson summary |
|
| Tests | Ping pong |
|||
"Forms of the struggle for existence"
| Comparative signs | Intraspecific struggle | Interspecies fight | Combating adverse environmental conditions |
| 1. Forms of manifestation of the struggle for existence | 1 Competition (competition). 2 Mutual assistance. | 1. Competition (competition). 2 Unilateral use of one type by another a) predator-prey; | Exposure to abiotic factors (frost, heat, rain, blizzards, flood, drought), which can strengthen or weaken intraspecific and interspecific struggle. |
| 2. Results of the struggle for existence | Leads to the preservation of the population and species due to the death or non-participation in reproduction of the least adapted individuals of a given species, that is, it leads to the prosperity of the species as a whole, contributes to its improvement. | Leads to the victory of the more viable individual, to the evolution of both interacting species, to the development of mutual adaptations in them. Means of attack: fangs, claws, fast movement, lurking behavior. Means of protection - spikes, shells, needles, toxic substances, camouflage coloring, etc. | Leads to the survival of the most adapted individuals, populations, and species in changed conditions of inanimate nature. |
| 3. Examples | Fight for territory; Competition for spoils; Intraspecific cannibalism (eating individuals of one's own species); The struggle for dominance in the pack; The struggle for possession of the female. | One species displaces another; They divide the territory; Switching to different foods; Predation. | Seasonal change of fur (in mammals); Summer and winter hibernation in animals; Seasonal migrations and migrations of birds; Adaptation of animals and plants to desert and tundra conditions (developed root system, reduced leaves, reserves of water and fat in the body, short stature of tundra plants, etc.) |
3. Disruptive (disruptive) selection carried out in cases where two or more genetically different forms have an advantage in different conditions, for example in different seasons of the year. Disruptive selection favors more than one phenotype and is directed against intermediate forms. It seems to tear the population according to this characteristic into several groups found in the same territory, and can, with the participation of isolation, lead to the division of the population into two or more.
Charles Darwin observed disruptive selection on oceanic islands, on which wingless insects and insects with very long wings appeared. Insects with medium wings were blown into the sea by the wind and died. Madagascar cockroaches, unlike American cockroaches, have no wings at all, but their tenacious legs allow them to climb even on a glass vertical plane. A discontinuous form of selection leads to polymorphism - the formation of several forms that differ in a certain trait (in the family of termites, bees, ants - there are queens, workers, soldiers, males).
Answer key:
Answer key: 1 s, 2 a, 3 s, 4 s, 5 v, 6 v, 7 v, 8 v, 9 a, 10 d.
____________________________________________________
Answer key: 1 s, 2 a, 3 s, 4 s, 5 v, 6 v, 7 v, 8 v, 9 a, 10 d.
____________________________________________________
Answer key: 1 s, 2 a, 3 s, 4 s, 5 v, 6 v, 7 v, 8 v, 9 a, 10 d.
____________________________________________________
Educational:
"It's hard to live in this world
There is no comfort in it,
The wind howls at dawn
The wolves are gnawing the bunny.”
Organizing time:
Competition No. 1 “Greetings”
Competition No. 2 “Warm-up”
- Author of the first evolutionary theory. (J.B. Lamarck)
Biological progress
Biological regression
- Increase in the number of individuals
- Evolutionary failure
- Evolutionary success
- Extinction
- Increase in the number of species
- Decline in species numbers
- Reduction in the number of individuals
- Narrowing of the occupied area
Competition No. 3 “Captain”
Recording in a notebook - by “struggle” we mean not a direct clash between individuals, leading to the displacement of some of them.
II. Learning new material:
A) intraspecific b) interspecific c) fight against unfavorable environmental conditions (abiotic factors).
Competition of plants of the same species for light in a pine or spruce forest
2. Interspecific struggle - exists between individuals of different species.
Intraspecific and interspecific struggle can be divided into direct and indirect. In direct fighting, an open clash of individuals occurs. Indirect - without open clashes.
3. There is another struggle for existence, which is called the struggle with abiotic factors - the relationship of organisms with the environment, i.e. the struggle for survival in natural disasters - floods, early frosts, fires, etc.
4. Lesson summary.
5.Homework
View document contents
“Lesson on the topic “The struggle for existence, its causes and types””
KSU "Mostikskaya Secondary School"
Biology lesson on the topic:
“The struggle for existence, its causes and types”
(9th grade)
Biology teacher: Golyashova E.V.
2015-2016 academic year
Lesson topic: The struggle for existence, its causes and types.
Lesson type: Learning new material.
The purpose of the lesson: Study of the causes of the struggle for existence and its types.
Tasks:
Educational:
study the struggle for existence as one of the main reasons for evolution
identify the causes of the struggle for existence
form a concept about the types of struggle for creatures
Educational:
develop students' cognitive interest
develop students’ independence, the ability to overcome learning difficulties
develop students' emotions (situation of surprise)
develop initiative and self-confidence
develop your skills to apply in practice
Educational:
nurturing learning motives and a positive attitude towards knowledge
Methods: Verbal-illustrative, demonstration
Forms: group, individual, game
"It's hard to live in this world
There is no comfort in it,
The wind howls at dawn
The wolves are gnawing the bunny.”
Organizing time:
Competition No. 1 “Greetings”
Competition No. 2 “Warm-up”
The driving force of evolution, making individuals of the same species diverse and providing material for selection. (variability)
The scientist who introduced the double Latin names into the system, which are still used today. (C. Linnaeus)
The scientist who was the first to correctly point out the role of the environment in determining the evolutionary changes of organisms. (J.B. Lamarck)
The process of gradual improvement of living organisms over a long period of time. (evolution)
An increase in the number of individuals, expansion of the range, evolutionary success can be called (biological progress)
A scientist who assumed that all useful changes acquired during training are inherited. (J.B. Lamarck)
A decrease in the number of individuals and species, a narrowing of the range, an evolutionary failure are called (biological regression)
The property of organisms to resemble their ancestors and pass on some characteristics to their offspring (heredity)
The process as a result of which predominantly individuals with hereditary changes that are useful under given conditions survive and leave behind offspring. (natural selection)
Establish a correspondence between evolutionary concepts and their definitions.
Increase in the number of individuals
Settlement over vast areas
Evolutionary failure
Evolutionary success
Extinction
Increase in the number of species
Decline in species numbers
Reduction in the number of individuals
Narrowing of the occupied area
Facts are given that illustrate one of the properties inherent in living things.
Distribute them accordingly.
Competition No. 3 “Captain”
The general property of organisms to produce more offspring than are capable of surviving under given specific conditions is called (overabundance)
What does overpopulation lead to? (to competition between individuals)
What does the struggle for existence lead to? (towards the survival of those better adapted to the environment)
Define the struggle for existence. (This is a set of diverse complex relationships between organisms and the environment)
What causes the struggle for existence and what types of struggle for existence exist, we will find out today in class.
To begin with, formulate an answer to me about how you understand the meaning of the phrase “struggle for existence.” (students' answers)
Writing in a notebook - by “struggle” we mean not a direct clash between special people, leading to the displacement of some of them.
II. Learning new material:
EVENTS AND FACTS: Even Charles Darwin believed that the struggle for existence is a consequence of two mutually exclusive reasons:
The unlimited ability of living organisms to reproduce.
Limited natural resources.
Speaking about the struggle for existence, we can distinguish three forms of the struggle for existence:
A) intraspecific b) interspecific c) fight against unfavorable environmental conditions (abiotic factors).
Let's take a closer look at each form.
1. Intraspecific struggle occurs between individuals of the same species. An example of such a struggle is the mating tournaments of deer, wolves, birds and other animals.
competition of plants of the same species for light in a pine or spruce forest 
Intraspecific struggle is the most acute form, during which the most individuals die.
Question: what are the causes of intraspecific struggle? (competition for food, for the female’s attention, for territory) i.e. individuals need the same limited resources.
Two birds run away from a wolf. One of them says to the other:
-"What are you hoping for? You still won't be able to run faster than a wolf."
“But I don’t need to run faster than the wolf, I need to run faster than you: then the wolf will get you, not me,” answers the other.
Hares compete in running speed not with wolves, but with each other.
A wolf who is chasing a hare is not competing with him, but with another wolf who is chasing another hare in another forest.
It is at the intraspecific level that interspecific struggle is realized!
2. Interspecific struggle - exists between individuals of different species. 
Let us remember the cartoon “Well, wait a minute”; there is also an interspecies struggle between the wolf and the hare.
Intraspecific and interspecific struggle can be divided into direct and indirect. In direct fighting, an open clash of individuals occurs. Indirect - without open clashes.
3. There is another struggle for existence, which is called the struggle with abiotic factors - the relationship of organisms with the environment, i.e. the struggle for survival in natural disasters - floods, early frosts, fires, etc.
4. Lesson summary. We have looked at various forms of struggle for existence. Sum up, draw a conclusion, what have we come to?
During the struggle for existence, individuals that are better adapted to environmental conditions survive and leave offspring. The struggle for existence leads to natural selection.
5.Homework clause 26. Answer questions orally under the letter B p. 121
Loading...
